Public bug reported:
I have 4 128GB Optane DC Persistent Memory devices in my server,
assigned to AppDirect access (i.e., accessed via memory-mapping at the
cache line level), and have run into a severe performance issue with the
latest kernel 5.0.0-31.
I realize that not many people have this storage type as yet, but it is
becoming increasingly important in the server world, so I think this bug
is pretty important.
Bug details:
When running with kernel 5.0.0-29, write access times to the Optane PM
devices are in the sub-microsecond range, as they should be.
When running with kernel 5.0.0-31, write access times are much slower,
averaging in the 30 microsecond range, until a large number of writes
(see below) have been executed. Then they return to normal speed.
My application is a hash table implementation optimized for the Optane
PM devices (see webpage at www.threemisses.com). Since it is a hash
table, it has very poor locality of reference, and is filled "randomly",
so I don't know exactly what the sequence of writes is.
However, I can say that the speed is very slow until the fill ratio of
the hash table is about 50%, then it returns to the normal sub-
microsecond range.
ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: linux-image-5.0.0-31-generic 5.0.0-31.33
ProcVersionSignature: Ubuntu 5.0.0-31.33-generic 5.0.21
Uname: Linux 5.0.0-31-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.10-0ubuntu27.1
Architecture: amd64
Date: Tue Oct 15 09:01:06 2019
InstallationDate: Installed on 2019-09-02 (42 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
IwConfig:
lo no wireless extensions.
eno0 no wireless extensions.
enp181s0f1 no wireless extensions.
MachineType: Supermicro SYS-7039A-I
ProcEnviron:
LD_LIBRARY_PATH=<set>
TERM=xterm-256color
PATH=(custom, no user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.0.0-31-generic
root=UUID=3239f211-86a3-44bb-8251-62037ebea848 ro transparent_hugepage=always
quiet splash nomodeset vt.handoff=1
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-5.0.0-31-generic N/A
linux-backports-modules-5.0.0-31-generic N/A
linux-firmware 1.178.3
RfKill:
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/06/2019
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 3.0a
dmi.board.asset.tag: ZM193S000653
dmi.board.name: X11DAi-N
dmi.board.vendor: Supermicro
dmi.board.version: 1.02
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 1
dmi.chassis.vendor: Supermicro
dmi.chassis.version: 123456789
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvr3.0a:bd03/06/2019:svnSupermicro:pnSYS-7039A-I:pvr123456789:rvnSupermicro:rnX11DAi-N:rvr1.02:cvnSupermicro:ct1:cvr123456789:
dmi.product.family: SMC X11
dmi.product.name: SYS-7039A-I
dmi.product.sku: 097A15D9
dmi.product.version: 123456789
dmi.sys.vendor: Supermicro
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug disco
** Description changed:
I have 4 128GB Optane DC Persistent Memory devices in my server,
assigned to AppDirect access (i.e., accessed via memory-mapping at the
cache line level), and have run into a severe performance issue with the
latest kernel 5.0.0-31.
I realize that not many people have this storage type as yet, but it is
- becoming increasingly important in the server world, so I think it is
- pretty important.
+ becoming increasingly important in the server world, so I think this bug
+ is pretty important.
Bug details:
When running with kernel 5.0.0-29, write access times to the Optane PM
devices are in the sub-microsecond range, as they should be.
When running with kernel 5.0.0-31, write access times are much slower,
averaging in the 30 microsecond range, until a large number of writes
(see below) have been executed. Then they return to normal speed.
My application is a hash table implementation optimized for the Optane
PM devices (see webpage at www.threemisses.com). Since it is a hash
table, it has very poor locality of reference, and is filled "randomly",
so I don't know exactly what the sequence of writes is.
However, I can say that the speed is very slow until the fill ratio of
the hash table is about 50%, then it returns to the normal sub-
microsecond range.
ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: linux-image-5.0.0-31-generic 5.0.0-31.33
ProcVersionSignature: Ubuntu 5.0.0-31.33-generic 5.0.21
Uname: Linux 5.0.0-31-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.10-0ubuntu27.1
Architecture: amd64
Date: Tue Oct 15 09:01:06 2019
InstallationDate: Installed on 2019-09-02 (42 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
IwConfig:
- lo no wireless extensions.
-
- eno0 no wireless extensions.
-
- enp181s0f1 no wireless extensions.
+ lo no wireless extensions.
+
+ eno0 no wireless extensions.
+
+ enp181s0f1 no wireless extensions.
MachineType: Supermicro SYS-7039A-I
ProcEnviron:
- LD_LIBRARY_PATH=<set>
- TERM=xterm-256color
- PATH=(custom, no user)
- LANG=en_US.UTF-8
- SHELL=/bin/bash
+ LD_LIBRARY_PATH=<set>
+ TERM=xterm-256color
+ PATH=(custom, no user)
+ LANG=en_US.UTF-8
+ SHELL=/bin/bash
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.0.0-31-generic
root=UUID=3239f211-86a3-44bb-8251-62037ebea848 ro transparent_hugepage=always
quiet splash nomodeset vt.handoff=1
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
- linux-restricted-modules-5.0.0-31-generic N/A
- linux-backports-modules-5.0.0-31-generic N/A
- linux-firmware 1.178.3
+ linux-restricted-modules-5.0.0-31-generic N/A
+ linux-backports-modules-5.0.0-31-generic N/A
+ linux-firmware 1.178.3
RfKill:
-
+
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/06/2019
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 3.0a
dmi.board.asset.tag: ZM193S000653
dmi.board.name: X11DAi-N
dmi.board.vendor: Supermicro
dmi.board.version: 1.02
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 1
dmi.chassis.vendor: Supermicro
dmi.chassis.version: 123456789
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvr3.0a:bd03/06/2019:svnSupermicro:pnSYS-7039A-I:pvr123456789:rvnSupermicro:rnX11DAi-N:rvr1.02:cvnSupermicro:ct1:cvr123456789:
dmi.product.family: SMC X11
dmi.product.name: SYS-7039A-I
dmi.product.sku: 097A15D9
dmi.product.version: 123456789
dmi.sys.vendor: Supermicro
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https://bugs.launchpad.net/bugs/1848212
Title:
Optane PM access times are much longer than they should be
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