U.S. patent application number 14/473121 was filed with the patent office on 2016-03-03 for thermally sensitive wear leveling for a flash memory device that includes a plurality of flash memory modules.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to KEITH M. CAMPBELL, WILLIAM M. MEGARITY, LUKE D. REMIS, GREGORY D. SELLMAN, CHRISTOPHER L. WOOD.
Application Number | 20160062676 14/473121 |
Document ID | / |
Family ID | 55402528 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160062676 |
Kind Code |
A1 |
CAMPBELL; KEITH M. ; et
al. |
March 3, 2016 |
THERMALLY SENSITIVE WEAR LEVELING FOR A FLASH MEMORY DEVICE THAT
INCLUDES A PLURALITY OF FLASH MEMORY MODULES
Abstract
Thermally sensitive wear leveling for a flash memory device that
includes a plurality of flash memory modules, the flash memory
device included in a computing system that includes a plurality of
additional computing components, including: identifying a thermal
sensitivity coefficient for each flash memory module in dependence
upon a physical topology of the flash memory device and one or more
of the additional computing components; identifying wear leveling
information for each flash memory module; receiving a request to
write data to the flash memory device; selecting, in dependence
upon the thermal sensitivity coefficient for each flash memory
module and the wear leveling information for each flash memory
module, a target flash memory module for servicing the request to
write data to the flash memory device; and writing the data to the
target flash memory module.
Inventors: |
CAMPBELL; KEITH M.; (CARY,
NC) ; MEGARITY; WILLIAM M.; (RALEIGH, NC) ;
REMIS; LUKE D.; (RALEIGH, NC) ; SELLMAN; GREGORY
D.; (MORRISVILLE, NC) ; WOOD; CHRISTOPHER L.;
(GREENVILLE, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
55402528 |
Appl. No.: |
14/473121 |
Filed: |
August 29, 2014 |
Current U.S.
Class: |
711/103 |
Current CPC
Class: |
G06F 3/0679 20130101;
G06F 3/0644 20130101; G06F 3/0616 20130101; G06F 3/0653 20130101;
G11C 16/3495 20130101 |
International
Class: |
G06F 3/06 20060101
G06F003/06; G11C 16/34 20060101 G11C016/34 |
Claims
1. A method of thermally sensitive wear leveling for a flash memory
device that includes a plurality of flash memory modules, the flash
memory device included in a computing system that includes a
plurality of additional computing components, the method
comprising: identifying a thermal sensitivity coefficient for each
flash memory module in dependence upon a physical topology of the
flash memory device and one or more of the additional computing
components; identifying wear leveling information for each flash
memory module; receiving a request to write data to the flash
memory device; selecting, in dependence upon the thermal
sensitivity coefficient for each flash memory module and the wear
leveling information for each flash memory module, a target flash
memory module for servicing the request to write data to the flash
memory device; and writing the data to the target flash memory
module.
2. The method of claim 1 wherein identifying a thermal sensitivity
coefficient for each flash memory module in dependence upon a
physical topology of the flash memory device and one or more of the
additional computing components further comprises determining a
distance between each flash memory module and a heat producing
computing component.
3. The method of claim 1 wherein identifying a thermal sensitivity
coefficient for each flash memory module in dependence upon a
physical topology of the flash memory device and one or more of the
additional computing components further comprises determining a
distance between each flash memory module and a heat reducing
computing component.
4. The method of claim 1 wherein identifying wear leveling
information for each flash memory module further comprises
determining a number of times that data has been written to each
flash memory module.
5. The method of claim 1 wherein selecting, in dependence upon the
thermal sensitivity coefficient for each flash memory module and
the wear leveling information for each flash memory module, a
target flash memory module for servicing the request to write data
to the flash memory device further comprises: identifying a least
utilized flash memory module; identifying a utilization discrepancy
threshold; and eliminating, from consideration as the target flash
memory module, one or more flash memory modules that have been
utilized more than the least utilized flash memory module by an
amount equal to or in excess of the utilization discrepancy
threshold.
6. The method of claim 1 wherein the flash memory device is a flash
dual in-line memory module (DIMM).
7. An apparatus for thermally sensitive wear leveling for a flash
memory device that includes a plurality of flash memory modules,
the apparatus including the flash memory device and a plurality of
additional computing components, the apparatus further comprising a
computer processor, a computer memory operatively coupled to the
computer processor, the computer memory having disposed within it
computer program instructions that, when executed by the computer
processor, cause the apparatus to carry out the steps of:
identifying a thermal sensitivity coefficient for each flash memory
module in dependence upon a physical topology of the flash memory
device and one or more of the additional computing components;
identifying wear leveling information for each flash memory module;
receiving a request to write data to the flash memory device;
selecting, in dependence upon the thermal sensitivity coefficient
for each flash memory module and the wear leveling information for
each flash memory module, a target flash memory module for
servicing the request to write data to the flash memory device; and
writing the data to the target flash memory module.
8. The apparatus of claim 7 wherein identifying a thermal
sensitivity coefficient for each flash memory module in dependence
upon a physical topology of the flash memory device and one or more
of the additional computing components further comprises
determining a distance between each flash memory module and a heat
producing computing component.
9. The apparatus of claim 7 wherein identifying a thermal
sensitivity coefficient for each flash memory module in dependence
upon a physical topology of the flash memory device and one or more
of the additional computing components further comprises
determining a distance between each flash memory module and a heat
reducing computing component.
10. The apparatus of claim 7 wherein identifying wear leveling
information for each flash memory module further comprises
determining a number of times that data has been written to each
flash memory module.
11. The apparatus of claim 7 wherein selecting, in dependence upon
the thermal sensitivity coefficient for each flash memory module
and the wear leveling information for each flash memory module, a
target flash memory module for servicing the request to write data
to the flash memory device further comprises: identifying a least
utilized flash memory module; identifying a utilization discrepancy
threshold; and eliminating, from consideration as the target flash
memory module, one or more flash memory modules that have been
utilized more than the least utilized flash memory module by an
amount equal to or in excess of the utilization discrepancy
threshold.
12. The apparatus of claim 7 wherein the flash memory device is a
flash dual in-line memory module (`DIMM`).
13. A computer program product for thermally sensitive wear
leveling for a flash memory device that includes a plurality of
flash memory modules, the flash memory device included in a
computing system that includes a plurality of additional computing
components, the computer program product disposed upon a computer
readable medium, the computer program product comprising computer
program instructions that, when executed, cause a computer to carry
out the steps of: identifying a thermal sensitivity coefficient for
each flash memory module in dependence upon a physical topology of
the flash memory device and one or more of the additional computing
components; identifying wear leveling information for each flash
memory module; receiving a request to write data to the flash
memory device; selecting, in dependence upon the thermal
sensitivity coefficient for each flash memory module and the wear
leveling information for each flash memory module, a target flash
memory module for servicing the request to write data to the flash
memory device; and writing the data to the target flash memory
module.
14. The computer program product of claim 13 wherein identifying a
thermal sensitivity coefficient for each flash memory module in
dependence upon a physical topology of the flash memory device and
one or more of the additional computing components further
comprises determining a distance between each flash memory module
and a heat producing computing component.
15. The computer program product of claim 13 wherein identifying a
thermal sensitivity coefficient for each flash memory module in
dependence upon a physical topology of the flash memory device and
one or more of the additional computing components further
comprises determining a distance between each flash memory module
and a heat reducing computing component.
16. The computer program product of claim 13 wherein identifying
wear leveling information for each flash memory module further
comprises determining a number of times that data has been written
to each flash memory module.
17. The computer program product of claim 13 wherein selecting, in
dependence upon the thermal sensitivity coefficient for each flash
memory module and the wear leveling information for each flash
memory module, a target flash memory module for servicing the
request to write data to the flash memory device further comprises:
identifying a least utilized flash memory module; identifying a
utilization discrepancy threshold; and eliminating, from
consideration as the target flash memory module, one or more flash
memory modules that have been utilized more than the least utilized
flash memory module by an amount equal to or in excess of the
utilization discrepancy threshold.
18. The computer program product of claim 13 wherein the flash
memory device is a flash dual in-line memory module (`DIMM`).
19. The computer program product of claim 13 wherein the computer
readable medium comprises a signal medium.
20. The computer program product of claim 13 wherein the computer
readable medium comprises a storage medium.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The field of the invention is data processing, or, more
specifically, methods, apparatus, and products for thermally
sensitive wear leveling for a flash memory device that includes a
plurality of flash memory modules.
[0003] 2. Description of Related Art
[0004] Modern computing devices can include storage devices that
utilized flash-based memory. The performance of such flash-based
memory, however, is only guaranteed to be reliable when the
flash-based memory is at a temperature that is below and
predetermined threshold. In addition, the performance of such
flash-based memory is also only guaranteed to be reliable when the
flash-based memory has been written to less than a predetermined
number of times.
SUMMARY OF THE INVENTION
[0005] Methods, apparatuses, and products for thermally sensitive
wear leveling for a flash memory device that includes a plurality
of flash memory modules, the flash memory device included in a
computing system that includes a plurality of additional computing
components, including: identifying a thermal sensitivity
coefficient for each flash memory module in dependence upon a
physical topology of the flash memory device and one or more of the
additional computing components; identifying wear leveling
information for each flash memory module; receiving a request to
write data to the flash memory device; selecting, in dependence
upon the thermal sensitivity coefficient for each flash memory
module and the wear leveling information for each flash memory
module, a target flash memory module for servicing the request to
write data to the flash memory device; and writing the data to the
target flash memory module.
[0006] The foregoing and other objects, features and advantages of
the invention will be apparent from the following more particular
descriptions of example embodiments of the invention as illustrated
in the accompanying drawings wherein like reference numbers
generally represent like parts of example embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 sets forth a block diagram of automated computing
machinery comprising an example computer useful in thermally
sensitive wear leveling for a flash memory device that includes a
plurality of flash memory modules according to embodiments of the
present invention.
[0008] FIG. 2 sets forth a flow chart illustrating an example
method for thermally sensitive wear leveling for a flash memory
device that includes a plurality of flash memory modules according
to embodiments of the present invention.
[0009] FIG. 3 sets forth a flow chart illustrating an additional
example method for thermally sensitive wear leveling for a flash
memory device that includes a plurality of flash memory modules
according to embodiments of the present invention.
[0010] FIG. 4 sets forth a flow chart illustrating an additional
example method for thermally sensitive wear leveling for a flash
memory device that includes a plurality of flash memory modules
according to embodiments of the present invention.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0011] Example methods, apparatuses, and products for thermally
sensitive wear leveling for a flash memory device in accordance
with the present invention are described with reference to the
accompanying drawings, beginning with FIG. 1. FIG. 1 sets forth a
block diagram of automated computing machinery comprising an
example computer (152) useful in thermally sensitive wear leveling
for a flash memory device (224) according to embodiments of the
present invention.
[0012] The computer (152) of FIG. 1 includes a flash memory device
(224) that includes a plurality of flash memory modules (226, 228,
230) according to embodiments of the present invention. The flash
memory device (224) is a form of computer storage that utilizes
flash-based memory to form non-volatile computer storage. The flash
memory device (224) may be embodied, for example, as a flash dual
in-line memory module (`DIMM`) where flash-based memory is packaged
onto a DIMM form factor that is inserted into a DIMM slot, as
Peripheral Component Interconnect Express (`PCIe`) flash device
where flash-based memory is packaged onto a PCIe expansion card
form factor that is inserted into a PCIe slot, and so on. Such
flash memory devices (224) may therefore provide non-volatile
memory to the computer (152) in form factors that are distinct from
traditional forms of non-volatile memory such as a traditional hard
disk drive.
[0013] The flash memory device (224) depicted in FIG. 1 includes a
plurality of flash memory modules (226, 228, 230). Each flash
memory modules (226, 228, 230) may be embodied, for example, as a
flash chip. Each flash memory module (226, 228, 230) may be arrayed
to achieve a total capacity for the flash memory device (224) that
is equal to the sum of the memory capacity for each of the flash
memory modules (226, 228, 230).
[0014] The flash memory device (224) depicted in FIG. 1 is included
in a computer (152) that includes a plurality of additional
computing components. The additional computing components of
interest may include any computing component that thermally impacts
the flash memory device (224) and the flash memory modules (226,
228, 230) contained therein. One example of an additional computing
component is a fan that draws cooler air into the case of the
computer (152) from the outside, expels warm air from inside the
case of the computer (152), or moves air across a heat sink or the
flash memory device (224) itself to cool the flash memory device
(224) and one or more of the flash memory modules (226, 228, 230)
contained therein. Another example of an additional computing
component is a computer processor (156) that generates heat during
operation, such that the heat generated by the computer processor
thermally impacts the flash memory device (224) and one or more of
the flash memory modules (226, 228, 230) contained therein. Yet
another example of an additional computing component is a DIMM
that, because of its location relative to the flash memory device
(224) and a fan, blocks the flow of air from the fan to the flash
memory device (224) and one or more of the flash memory modules
(226, 228, 230) contained therein.
[0015] Readers will appreciate that because certain flash memory
modules (226, 228, 230) may be closer to heat generating sources
such a computer processor, certain flash memory modules (226, 228,
230) may be exposed to more externally generated heat than other
flash memory modules (226, 228, 230). Readers will similarly
appreciate that because certain flash memory modules (226, 228,
230) may be closer to heat removing sources such a computer fan,
certain flash memory modules (226, 228, 230) may have heat removed
more efficiently than other flash memory modules (226, 228, 230).
As such, each flash memory module (226, 228, 230) may be thermally
impacted by its physical surroundings in a different manner.
[0016] The computer depicted in FIG. 1 carries out thermally
sensitive wear leveling for a flash memory device (224) in
accordance with the present invention by identifying a thermal
sensitivity coefficient for each flash memory module (226, 228,
230), identifying wear leveling information for each flash memory
module (226, 228, 230), receiving a request to write data to the
flash memory device (224), selecting a target flash memory module
(226, 228, 230) for servicing the request to write data to the
flash memory device (224) in dependence upon the thermal
sensitivity coefficient for each flash memory module (226, 228,
230) and the wear leveling information for each flash memory module
(226, 228, 230), and writing the data to the target flash memory
module (224), as described in greater detail below.
[0017] The computer (152) of FIG. 1 also includes at least one
computer processor (156) or `CPU` as well as random access memory
(168) (`RAM`) which is connected through a high speed memory bus
(166) and bus adapter (158) to processor (156) and to other
components of the computer (152). Stored in RAM (168) is an
operating system (154). Operating systems useful for thermally
sensitive wear leveling for a flash memory device (224) that
includes a plurality of flash memory modules (226, 228, 230)
according to embodiments of the present invention include UNIX.TM.,
Linux.TM., Microsoft XP.TM., AIX.TM., IBM's i5/OS.TM., and others
as will occur to those of skill in the art. The operating system
(154) is shown in RAM (168) but readers will appreciate that such
software may alternatively be stored in non-volatile memory such
as, for example, on a disk drive (170) or on the flash memory
device (224).
[0018] The computer (152) of FIG. 1 includes disk drive adapter
(172) coupled through expansion bus (160) and bus adapter (158) to
processor (156) and other components of the computer (152). Disk
drive adapter (172) connects non-volatile data storage to the
computer (152) in the form of disk drive (170). Disk drive adapters
useful in computers for thermally sensitive wear leveling for a
flash memory device (224) that includes a plurality of flash memory
modules (226, 228, 230) according to embodiments of the present
invention include Integrated Drive Electronics (`IDE`) adapters,
Small Computer System Interface (`SCSI`) adapters, and others as
will occur to those of skill in the art. Non-volatile computer
memory also may be implemented for as an optical disk drive,
electrically erasable programmable read-only memory (so-called
`EEPROM` or `Flash` memory), RAM drives, and so on, as will occur
to those of skill in the art.
[0019] The example computer (152) of FIG. 1 includes one or more
input/output (`I/O`) adapters (178). I/O adapters implement
user-oriented input/output through, for example, software drivers
and computer hardware for controlling output to display devices
such as computer display screens, as well as user input from user
input devices (181) such as keyboards and mice. The example
computer (152) of FIG. 1 includes a video adapter (209), which is
an example of an I/O adapter specially designed for graphic output
to a display device (180) such as a display screen or computer
monitor. Video adapter (209) is connected to processor (156)
through a high speed video bus (164), bus adapter (158), and the
front side bus (162), which is also a high speed bus.
[0020] The example computer (152) of FIG. 1 includes a
communications adapter (167) for data communications with other
computers (182) and for data communications with a data
communications network (100). Such data communications may be
carried out serially through RS-232 connections, through external
buses such as a Universal Serial Bus (`USB`), through data
communications networks such as IP data communications networks,
and in other ways as will occur to those of skill in the art.
Communications adapters implement the hardware level of data
communications through which one computer sends data communications
to another computer, directly or through a data communications
network. Examples of communications adapters useful for thermally
sensitive wear leveling for a flash memory device that includes a
plurality of flash memory modules according to embodiments of the
present invention include modems for wired dial-up communications,
Ethernet (IEEE 802.3) adapters for wired data communications
network communications, and 802.11 adapters for wireless data
communications network communications.
[0021] For further explanation, FIG. 2 sets forth a flow chart
illustrating an example method for thermally sensitive wear
leveling for a flash memory device (224) that includes a plurality
of flash memory modules (226, 228, 230) according to embodiments of
the present invention. The flash memory device (224) depicted in
FIG. 2 is a form of computer storage that utilizes flash-based
memory to form non-volatile computer storage. The flash memory
device (224) may be embodied, for example, as a flash DIMM where
flash-based memory is packaged onto a DIMM form factor that is
inserted into a DIMM slot, as PCIe flash where flash-based memory
is packaged onto a PCIe expansion card form factor that is inserted
into a PCIe slot, and so on. Such flash memory devices (224) may
therefore provide non-volatile memory to the computing system (202)
in form factors that are distinct from traditional forms of
non-volatile memory such as a traditional hard disk drive.
[0022] The flash memory device (224) depicted in FIG. 2 includes a
plurality of flash memory modules (226, 228, 230). Each flash
memory modules (226, 228, 230) may be embodied, for example, as a
flash chip. Each flash memory module (226, 228, 230) may be arrayed
to achieve a total capacity for the flash memory device (224) that
is equal to the sum of the memory capacity for each of the flash
memory modules (226, 228, 230).
[0023] The flash memory device (224) depicted in FIG. 2 is included
in a computing system (202). The computing system (202) depicted in
FIG. 2 includes a plurality of additional computing components
(232). The additional computing components (232) of interest may
include any computing component that thermally impacts the flash
memory device (224) and the flash memory modules (226, 228, 230)
contained therein. One example of an additional computing component
(232) is a fan that draws cooler air into the case of the computing
system (202) from outside the case, expels warm air from inside the
case of the computing system (202), or moves air across a heat sink
the flash memory device (224) itself to cool the flash memory
device (224) and one or more of the flash memory modules (226, 228,
230) contained therein. Another example of an additional computing
component (232) is a computer processor that generates heat during
operation, such that the heat generated by the computer processor
thermally impacts the flash memory device (224) and one or more of
the flash memory modules (226, 228, 230) contained therein. Yet
another example of an additional computing component (232) is a
DIMM that, because of its location relative to the flash memory
device (224) and a fan, blocks the flow of air from the fan to the
flash memory device (224) and one or more of the flash memory
modules (226, 228, 230) contained therein.
[0024] Readers will appreciate that because certain flash memory
modules (226, 228, 230) may be closer to heat generating sources
such a computer processor, certain flash memory modules (226, 228,
230) may be exposed to more externally generated heat than other
flash memory modules (226, 228, 230). Readers will similarly
appreciate that because certain flash memory modules (226, 228,
230) may be closer to heat removing sources such a computer fan,
certain flash memory modules (226, 228, 230) may have heat removed
more efficiently than other flash memory modules (226, 228, 230).
As such, each flash memory module (226, 228, 230) may be thermally
impacted by its physical surroundings in a different manner.
[0025] The example method depicted in FIG. 2 includes identifying
(208) a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230). The thermal sensitivity coefficient (210)
for a particular flash memory module (226, 228, 230) represents the
extent to which a particular flash memory module (226, 228, 230)
may be thermally impacted by one or more of the additional
computing components (232) in the computing system. The thermal
sensitivity coefficient (210) may therefore be embodied as a
relative value where, for example, the thermal sensitivity
coefficient (210) associated with a first flash memory module (226)
is larger in value than the thermal sensitivity coefficient (210)
associated with a second flash memory module (228) when the one or
more of the additional computing components (232) expose the first
flash memory module (226) to more heat (or less heat removal) than
the second flash memory module (228). For example, the flash memory
module (226, 228, 230) that is closest to a particular heat
generating computer processor may have the highest thermal
sensitivity coefficient (210) while the flash memory module (226,
228, 230) that is furthest away from the heat generating computer
processor may have the lowest thermal sensitivity coefficient
(210). In an alternative and non-exclusive example, the flash
memory module (226, 228, 230) that is furthest away from a computer
fan may have the highest thermal sensitivity coefficient (210)
while the flash memory module (226, 228, 230) that is closest to
the computer fan may have the lowest thermal sensitivity
coefficient (210). While the examples included above describe a
higher thermal sensitivity coefficient (210) as being associated
with the flash memory module (226, 228, 230) that is most
negatively thermally impacted by the one or more of the additional
computing components (232), such an embodiment is only included for
explanation and does represent a limitation of the present
invention.
[0026] In the example depicted in FIG. 2, the thermal sensitivity
coefficient (210) for a particular flash memory module (226, 228,
230) is identified (208) in dependence upon a physical topology of
the flash memory device (224) and one or more of the additional
computing components (232). The physical topology of the flash
memory device (224) and one or more of the additional computing
components (232) may include, for example, the distance between
each flash memory module (226, 228, 230) on the flash memory device
(224) and one or more of the additional computing components (232),
the orientation of each flash memory module (226, 228, 230) on the
flash memory device (224) and one or more of the additional
computing components (232), and so on.
[0027] In the example method depicted in FIG. 2, identifying (208)
a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230) may be carried out, for example, by
providing a user interface to a system administrator and receiving
a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230) from the system administrator via the user
interface, by examining a specification of a board layout and
determining the relative distance between a thermally beneficial
computing component (e.g., a computer fan) and each flash memory
module (226, 228, 230), by examining a specification of a board
layout and determining the relative distance between a thermally
detrimental computing component (e.g., a computer processor) and
each flash memory module (226, 228, 230), by receiving a thermal
sensitivity coefficient (210) for each flash memory module (226,
228, 230) as part of a specification of a board layout, and so
on.
[0028] The example method depicted in FIG. 2 also includes
identifying (212) wear leveling information (214) for each flash
memory module (226, 228, 230). The wear leveling information (214)
for each flash memory module (226, 228, 230) may include
information identifying the extent to which a particular flash
memory module (226, 228, 230) has been utilized. Such wear leveling
information (214) can include, for example, the total number of
times that data has been written to a particular flash memory
module (226, 228, 230). Identifying (212) wear leveling information
(214) for each flash memory module (226, 228, 230) may therefore be
carried out by tracking the number of times that a particular flash
memory module (226, 228, 230) has been written to, by requesting,
from a system management module or other administrator, information
describing the number of times that a particular flash memory
module (226, 228, 230) has been written to, and so on. In the
example method depicted in FIG. 2, the wear leveling information
(214) may be utilized to facilitate `wear leveling` of the flash
memory modules (226, 228, 230) of the flash memory device
(224).
[0029] Wear leveling of the flash memory modules (226, 228, 230) of
the flash memory device (224) is carried out by equally, at least
within a predetermined tolerance, distributing write accesses to
flash memory modules (226, 228, 230) of the flash memory device
(224). Wear leveling is important in view of the fact that memory
cells and memory blocks becomes worn out and unreliable the more
frequently that data is written to the memory cells and the memory
blocks. As such, if the memory controller (206) operated by writing
data to one flash memory module (226) in the flash memory device
(224) much more frequently than another flash memory module (230)
of the flash memory device (224), the flash memory module (226)
that is written to more frequently would become worn out and
unreliable while other flash memory modules (228, 230) in the flash
memory device (224) that are written to less frequently would still
function properly. In order to avoid prematurely wearing out
certain flash memory modules (226, 228, 230) of the flash memory
device (224) while simultaneously underutilizing properly
functioning flash memory modules (226, 228, 230) of the flash
memory device (224), a predictive failure algorithm may be utilized
to intelligently distribute write accesses in a relatively uniform
manner across all flash memory modules (226, 228, 230) of the flash
memory device (224), such that each flash memory module (226, 228,
230) of the flash memory device (224) wears out in a relatively
uniform manner. The wear leveling information (214) may therefore
be utilized to steer new write access requests to those flash
memory modules (226, 228, 230) that have been written to less
frequently.
[0030] The example method depicted in FIG. 2 also includes
receiving (216) a request (204) to write data to the flash memory
device (224). In the example method depicted in FIG. 2, the request
(204) to write data to the flash memory device (224) may be
received by the memory controller (206). Such a request (204) may
be generated by a computer processor or other form of computer
logic and may include, for example, the size of data to be written
to the flash memory device (224), the actual data that is to be
written to the flash memory device (224), and so on.
[0031] The example method depicted in FIG. 2 also includes
selecting (218), in dependence upon the thermal sensitivity
coefficient (210) for each flash memory module (226, 228, 230) and
the wear leveling information (214) for each flash memory module
(226, 228, 230), a target flash memory module (226, 228, 230) for
servicing the request (204) to write data to the flash memory
device (224). In the example method depicted in FIG. 2, the target
flash memory module (226, 228, 230) for servicing the request (204)
to write data to the flash memory device (224) represents the flash
memory module (226, 228, 230) that data will be written to in
response to the request (204). Such a target flash memory module
(226, 228, 230) will not only be selected (218) by taking into
account the wear leveling information (214) for each flash memory
module (226, 228, 230), but such a target flash memory module (226,
228, 230) will be selected (218) by also taking into account the
thermal sensitivity coefficient (210) for each flash memory module
(226, 228, 230), so as to write data to the flash memory module
(226, 228, 230) in a thermally cognizant manner.
[0032] As described above, a predictive failure algorithm may carry
out wear leveling of the flash memory device (224) by taking into
account the number of times that a particular flash memory module
(226, 228, 230) has been written to when determining which location
in the flash memory device (224) that data should be written to in
response to the memory controller (206) receiving a request (204)
to write data to the flash memory device (224). The predictive
failure algorithm may also take into account the extent to which a
particular flash memory module (226, 228, 230) is thermally
impacted by additional computing components (232) in the computing
system (202) when determining which location in the flash memory
device (224) data should be written to in response to the memory
controller (206) receiving a request (204) to write data to the
flash memory device (224).
[0033] Consider an example in which the thermal sensitivity
coefficient (210) for each flash memory module (226, 228, 230) is
determined based on the proximity of each flash memory module (226,
228, 230) to a heat generating computer processor. In such an
example, the predictive failure algorithm may be structured such
that during periods of time in which the computer processor is
executing a large number of instructions (and thereby generating a
large amount of heat), flash memory modules (226, 228, 230) whose
thermal sensitivity coefficients (210) indicate that the flash
memory modules (226, 228, 230) are furthest away from the computer
processor are targeted for servicing write access requests. The
predictive failure algorithm may be similarly structured such that
during periods of time in which the computer processor is executing
a small number of instructions (and thereby not generating a large
amount of heat), flash memory modules (226, 228, 230) whose thermal
sensitivity coefficients (210) indicate that the flash memory
modules (226, 228, 230) are closest to the computer processor are
targeted for servicing write access requests. In such a way, flash
memory modules (226, 228, 230) that are more sensitive to heat
produced by the computer processor are utilized when the computer
processor is not generating much heat while flash memory modules
(226, 228, 230) that are less sensitive to heat produced by the
computer processor are utilized when the computer processor is
generating larger amounts of heat.
[0034] For further explanation, consider an additional example in
which the thermal sensitivity coefficients (210) for each flash
memory module (226, 228, 230) are identified based on the proximity
of each flash memory module (226, 228, 230) to a computer fan. In
such an example, the predictive failure algorithm may be structured
such that during periods of time in which a large number of write
access requests are being serviced by the flash memory device (224)
(thereby causing the flash memory device to generate a relatively
large amount of heat), flash memory modules (226, 228, 230) whose
thermal sensitivity coefficients (210) indicate that the flash
memory modules (226, 228, 230) are closest to computer fans are
targeted for servicing write access requests. The predictive
failure algorithm may be similarly structured such that during
periods of time in which a smaller number of write access requests
are being serviced by the flash memory device (224) (thereby
causing the flash memory device to generate a relatively small
amount of heat), the flash memory modules (226, 228, 230) whose
thermal sensitivity coefficients (210) indicate that the flash
memory modules (226, 228, 230) are furthest from the computer fans
may be targeted for servicing write access requests. In such a way,
flash memory modules (226, 228, 230) that are more efficiently
cooled by the computer fan are utilized when the flash memory
modules (226, 228, 230) are generating larger amounts of heat while
flash memory modules (226, 228, 230) that are less efficiently
cooled by the computer fan are utilized when the flash memory
modules (226, 228, 230) are generating smaller amounts of heat.
[0035] In the example method depicted in FIG. 2, selecting (218) a
target flash memory module (226, 228, 230) for servicing the
request (204) to write data to the flash memory device (224) may be
carried out by applying a predictive failure algorithm that
utilizes both wear leveling information (214) for each flash memory
module (226, 228, 230) and the thermal sensitivity coefficient
(210) for each flash memory module (226, 228, 230) as inputs.
Consider, an as example of such a predictive failure algorithm, a
predictive failure algorithm that generates a score for each flash
memory module (226, 228, 230) as follows:
Score=TW+(TC*WA),
where TW is equal to the total number of write accesses previously
serviced by a particular flash memory module (226, 228, 230), TC is
the thermal sensitivity coefficient (210) for a particular flash
memory module (226, 228, 230), and WA is the number of write
accesses directed to the flash memory device (224) during a
predetermined period of time. In such an example, assume that the
flash memory module (226, 228, 230) associated with the lowest
score will be selected (218) to service the request (204) to write
data to the flash memory device (224). Further assume that a low
thermal sensitivity coefficient (210) means that a particular
memory module (226, 228, 230) is less affected by heat generated by
other computing components.
[0036] By utilizing the predictive failure algorithm included
above, a flash memory module (226, 228, 230) that has previously
serviced a relatively high number of write accesses will have one
component (TW) of the predictive failure algorithm driving its
score higher than a flash memory module (226, 228, 230) that has
previously serviced a relatively low number of write accesses,
thereby promoting wear leveling. In addition, during periods where
the number of write accesses that are directed to the flash memory
device (214) is relatively large, the score for a flash memory
module (226, 228, 230) with a relatively high thermal sensitivity
coefficient (210) is more heavily impacted than would occur during
periods where the number of write accesses that are directed to the
flash memory device (214) is relatively small, thereby making it
less likely that a flash memory module (226, 228, 230) with a
relatively high thermal sensitivity coefficient (210) would be
selected for servicing a write access during periods of heavy
activity where the flash memory device (210) is exposed to large
amounts of heat.
[0037] Consider an example in which a first flash memory module
(226) has previously serviced 11,000 write accesses and a second
memory flash module (228) has previously serviced 10,000 write
accesses. Assume in such an example that the first flash memory
module (226) is not very sensitive to heat generated by other
computing components and therefore has a thermal sensitivity
coefficient (210) of 0.1, while the second flash memory module
(228) is very sensitive to heat generated by other computing
components and therefore has a thermal sensitivity coefficient
(210) of 0.9. In a situation where the number of write accesses
serviced by the flash memory device (224) is relatively low (e.g.,
5 write accesses in the immediately preceding predetermined period
of time), the second flash memory module (228) will be selected by
virtue of its low number of previously serviced write accesses and
in spite of its relatively high sensitivity to heat generated by
the other computing components. In a situation where the number of
write accesses serviced by the flash memory device (224) is
relatively high (e.g., 10,000 write accesses in the immediately
preceding predetermined period of time), however, the first flash
memory module (226) will be selected by virtue of its relatively
low sensitivity to heat generated by the other computing components
and in spite of its higher number of previously serviced write
accesses. Readers will appreciate that in the example described
above, less thermally sensitive flash memory modules will be more
heavily utilized during periods of high activity, while during
periods of low activity wear leveling considerations will control.
Readers will further appreciate that as a discrepancy in the number
of write accesses increases between two flash memory modules,
however, the less utilized flash memory module will eventually be
more heavily utilized.
[0038] The example method depicted in FIG. 2 also includes writing
(220) the data (222) to the target flash memory module (224). In
the example method depicted in FIG. 2, writing (220) the data (222)
to the target flash memory module (224) may be carried out by
writing data associated with the request (204) to a location with
the flash memory module (224) selected (218) for servicing the
request (204) to write data to the flash memory device (224).
[0039] Readers will appreciate that the steps described above may
be carried out by a system management module, a memory controller,
or any combination thereof. In fact, the steps described above may
be carried out by computer software executing on computer hardware
in the computing system (202), by special purpose computer logic
such as a circuit, controller, field-programmable gate array
(`FPGA`), or other form of computer logic included in the computing
system (202), or by any combination thereof.
[0040] For further explanation, FIG. 3 sets forth a flow chart
illustrating an additional example method for thermally sensitive
wear leveling for a flash memory device (224) that includes a
plurality of flash memory modules (226, 228, 230) according to
embodiments of the present invention. The example method depicted
in FIG. 3 is similar to the example method depicted in FIG. 2, as
the example method depicted in FIG. 3 also includes identifying
(208) a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230), identifying (212) wear leveling information
(214) for each flash memory module (226, 228, 230), receiving (216)
a request (204) to write data to the flash memory device (224),
selecting (218) a target flash memory module (226, 228, 230) for
servicing the request (204) to write data to the flash memory
device (224), and writing (220) the data (222) to the target flash
memory module (224).
[0041] In the example method depicted in FIG. 3, identifying (208)
a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230) can include determining (302) a distance
between each flash memory module (226, 228, 230) and a heat
producing computing component. Examples of heat producing computing
components can include processors, controllers, logic devices,
busses, or any other mechanical component in a computing system
that can produce heat during its operation. The distance between
each flash memory module (226, 228, 230) and a heat producing
computing component may be expressed in absolute terms such as, for
example, a number of millimeters between each flash memory module
(226, 228, 230) and the heat producing computing component. The
distance between each flash memory module (226, 228, 230) and a
heat producing computing component may alternatively be expressed
in relative terms such as a ranking of each flash memory module
(226, 228, 230) as being closest, second closest, third closest,
and so on to a heat producing computing component. In the example
method depicted in FIG. 3, determining (302) a distance between
each flash memory module (226, 228, 230) and a heat producing
computing component may be carried out, for example, by receiving
such information from a system administrator, by extracting such
information from a specification of a board design, and so on.
[0042] In the example method depicted in FIG. 3, identifying (208)
a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230) can alternatively include determining (304)
a distance between each flash memory module (226, 228, 230) and a
heat reducing computing component. Examples of heat reducing
computing components can include computer fans, heat sinks, or any
other mechanical component in a computing system that can remove
heat from the computing system during its operation. The distance
between each flash memory module (226, 228, 230) and a heat
reducing computing component may be expressed in absolute terms
such as, for example, a number of millimeters between each flash
memory module (226, 228, 230) and the heat reducing computing
component. The distance between each flash memory module (226, 228,
230) and a heat reducing computing component may alternatively be
expressed in relative terms such as a ranking of each flash memory
module (226, 228, 230) as being closest, second closest, third
closest, and so on to a heat reducing computing component. In the
example method depicted in FIG. 3, identifying (304) a physical
proximity of each flash memory module (226, 228, 230) to a heat
reducing computing component may be carried out, for example, by
receiving such information from a system administrator, by
extracting such information from a specification of a board design,
and so on.
[0043] Although steps 302 and 304 are described above as being
alternative embodiments, readers will appreciate that identifying
(208) a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230) can include both determining (302) a
distance between each flash memory module (226, 228, 230) and a
heat producing computing component and determining (304) a distance
between each flash memory module (226, 228, 230) and a heat
reducing computing component. Furthermore, multiple heat producing
computing components and multiple heat reducing computing
components may be taken into account when identifying (208) a
thermal sensitivity coefficient (210) for each flash memory module
(226, 228, 230).
[0044] In the example method depicted in FIG. 3, identifying (212)
wear leveling information (214) for each flash memory module (226,
228, 230) can include determining (306) a number of times that data
has been written to each flash memory module (226, 228, 230).
Determining (306) a number of times that data has been written to
each flash memory module (226, 228, 230) may be carried out, for
example, by maintaining a counter associated with each flash memory
module (226, 228, 230), where the counter associated with a
particular flash memory module (226, 228, 230) that is incremented
each time data is written to the particular flash memory module
(226, 228, 230).
[0045] For further explanation, FIG. 4 sets forth a flow chart
illustrating an additional example method for thermally sensitive
wear leveling for a flash memory device (224) that includes a
plurality of flash memory modules (226, 228, 230) according to
embodiments of the present invention. The example method depicted
in FIG. 4 is similar to the example method depicted in FIG. 2, as
the example method depicted in FIG. 4 also includes identifying
(208) a thermal sensitivity coefficient (210) for each flash memory
module (226, 228, 230), identifying (212) wear leveling information
(214) for each flash memory module (226, 228, 230), receiving (216)
a request (204) to write data to the flash memory device (224),
selecting (218) a target flash memory module (226, 228, 230) for
servicing the request (204) to write data to the flash memory
device (224), and writing (220) the data (222) to the target flash
memory module (224).
[0046] In the example method depicted in FIG. 4, selecting (218) a
target flash memory module (226, 228, 230) for servicing the
request (204) to write data to the flash memory device (224) can
include identifying (402) a least utilized flash memory module
(226, 228, 230). The least utilized flash memory module (226, 228,
230) may be identified (402), for example, by identifying the flash
memory module (226, 228, 230) that has serviced the least amount of
write accesses. In such an example, identifying (402) the least
utilized flash memory module (226, 228, 230) may therefore be
carried out by comparing the number of times that data has been
written to each flash memory module (226, 228, 230) and identifying
the flash memory module (226, 228, 230) that has been written to
the least amount of times.
[0047] In the example method depicted in FIG. 4, selecting (218) a
target flash memory module (226, 228, 230) for servicing the
request (204) to write data to the flash memory device (224) can
also include identifying (404) a utilization discrepancy threshold.
The utilization discrepancy threshold represents the extent to
which one flash memory module (226, 228, 230) may be utilized more
heavily than another flash memory module (226, 228, 230). The
utilization discrepancy threshold may be specified, for example, as
a numerical value specifying the amount of times that one flash
memory module (226, 228, 230) may be written to more than another
flash memory module (226, 228, 230). Identifying (404) a
utilization discrepancy threshold may be carried out, for example,
by receiving the utilization discrepancy threshold from a system
administrator, by extracting the utilization discrepancy threshold
from a system configuration file, and so on.
[0048] In the example method depicted in FIG. 4, selecting (218) a
target flash memory module (226, 228, 230) for servicing the
request (204) to write data to the flash memory device (224) can
also include eliminating (406), from consideration as the target
flash memory module, one or more flash memory modules (226, 228,
230) that have been utilized more than the least utilized flash
memory module by an amount that is equal to or in excess of the
utilization discrepancy threshold. Consider an example in which a
first flash memory module (226) has serviced 11,000 write access
requests and a second flash memory module (228) has serviced 10,000
write access requests, where the utilization discrepancy threshold
is set to a value of 1000 writes. In such an example, the first
flash memory module (226) would be eliminated (406) from
consideration as the target flash memory module, such that a flash
memory module (228, 230) other than the first flash memory module
(226) would be selected (218) as the target flash memory module and
thereby designated to service the request (204) to write data to
the flash memory device (224). In such an example, the first flash
memory module (226) would remain eliminated (406) from
consideration as the target flash memory module until the number of
write accesses serviced by the first flash memory module (226)
exceeds the number of write accesses serviced by the least utilized
flash memory module by a value that is less than the utilization
discrepancy threshold.
[0049] The present invention may be a system, a method, and/or a
computer program product. The computer program product may include
a computer readable storage medium (or media) having computer
readable program instructions thereon for causing a processor to
carry out aspects of the present invention.
[0050] The computer readable storage medium can be a tangible
device that can retain and store instructions for use by an
instruction execution device. The computer readable storage medium
may be, for example, but is not limited to, an electronic storage
device, a magnetic storage device, an optical storage device, an
electromagnetic storage device, a semiconductor storage device, or
any suitable combination of the foregoing. A non-exhaustive list of
more specific examples of the computer readable storage medium
includes the following: a portable computer diskette, a hard disk,
a random access memory (RAM), a read-only memory (ROM), an erasable
programmable read-only memory (EPROM or Flash memory), a static
random access memory (SRAM), a portable compact disc read-only
memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a
floppy disk, a mechanically encoded device such as punch-cards or
raised structures in a groove having instructions recorded thereon,
and any suitable combination of the foregoing. A computer readable
storage medium, as used herein, is not to be construed as being
transitory signals per se, such as radio waves or other freely
propagating electromagnetic waves, electromagnetic waves
propagating through a waveguide or other transmission media (e.g.,
light pulses passing through a fiber-optic cable), or electrical
signals transmitted through a wire.
[0051] Computer readable program instructions described herein can
be downloaded to respective computing/processing devices from a
computer readable storage medium or to an external computer or
external storage device via a network, for example, the Internet, a
local area network, a wide area network and/or a wireless network.
The network may comprise copper transmission cables, optical
transmission fibers, wireless transmission, routers, firewalls,
switches, gateway computers and/or edge servers. A network adapter
card or network interface in each computing/processing device
receives computer readable program instructions from the network
and forwards the computer readable program instructions for storage
in a computer readable storage medium within the respective
computing/processing device.
[0052] Computer readable program instructions for carrying out
operations of the present invention may be assembler instructions,
instruction-set-architecture (ISA) instructions, machine
instructions, machine dependent instructions, microcode, firmware
instructions, state-setting data, or either source code or object
code written in any combination of one or more programming
languages, including an object oriented programming language such
as Smalltalk, C++ or the like, and conventional procedural
programming languages, such as the "C" programming language or
similar programming languages. The computer readable program
instructions may execute entirely on the user's computer, partly on
the user's computer, as a stand-alone software package, partly on
the user's computer and partly on a remote computer or entirely on
the remote computer or server. In the latter scenario, the remote
computer may be connected to the user's computer through any type
of network, including a local area network (LAN) or a wide area
network (WAN), or the connection may be made to an external
computer (for example, through the Internet using an Internet
Service Provider). In some embodiments, electronic circuitry
including, for example, programmable logic circuitry,
field-programmable gate arrays (FPGA), or programmable logic arrays
(PLA) may execute the computer readable program instructions by
utilizing state information of the computer readable program
instructions to personalize the electronic circuitry, in order to
perform aspects of the present invention.
[0053] Aspects of the present invention are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatus (systems), and computer program products
according to embodiments of the invention. It will be understood
that each block of the flowchart illustrations and/or block
diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer readable
program instructions.
[0054] These computer readable program instructions may be provided
to a processor of a general purpose computer, special purpose
computer, or other programmable data processing apparatus to
produce a machine, such that the instructions, which execute via
the processor of the computer or other programmable data processing
apparatus, create means for implementing the functions/acts
specified in the flowchart and/or block diagram block or blocks.
These computer readable program instructions may also be stored in
a computer readable storage medium that can direct a computer, a
programmable data processing apparatus, and/or other devices to
function in a particular manner, such that the computer readable
storage medium having instructions stored therein comprises an
article of manufacture including instructions which implement
aspects of the function/act specified in the flowchart and/or block
diagram block or blocks.
[0055] The computer readable program instructions may also be
loaded onto a computer, other programmable data processing
apparatus, or other device to cause a series of operational steps
to be performed on the computer, other programmable apparatus or
other device to produce a computer implemented process, such that
the instructions which execute on the computer, other programmable
apparatus, or other device implement the functions/acts specified
in the flowchart and/or block diagram block or blocks.
[0056] The flowchart and block diagrams in the Figures illustrate
the architecture, functionality, and operation of possible
implementations of systems, methods, and computer program products
according to various embodiments of the present invention. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of instructions, which comprises one
or more executable instructions for implementing the specified
logical function(s). In some alternative implementations, the
functions noted in the block may occur out of the order noted in
the figures. For example, two blocks shown in succession may, in
fact, be executed substantially concurrently, or the blocks may
sometimes be executed in the reverse order, depending upon the
functionality involved. It will also be noted that each block of
the block diagrams and/or flowchart illustration, and combinations
of blocks in the block diagrams and/or flowchart illustration, can
be implemented by special purpose hardware-based systems that
perform the specified functions or acts or carry out combinations
of special purpose hardware and computer instructions.
[0057] It will be understood from the foregoing description that
modifications and changes may be made in various embodiments of the
present invention without departing from its true spirit. The
descriptions in this specification are for purposes of illustration
only and are not to be construed in a limiting sense. The scope of
the present invention is limited only by the language of the
following claims.
* * * * *