apport information
** Attachment added: "WifiSyslog.txt"
https://bugs.launchpad.net/bugs/1758621/+attachment/5136314/+files/WifiSyslog.txt
** Changed in: linux (Ubuntu)
Status: Incomplete => Confirmed
** Tags added: bionic
** Description changed:
Hi Ubuntu,
Just found out today that when using Ubuntu Xenial HWE kernel 4.13 in a
VM on top of Proxmox VE 5.1.x, the direct synchronous write performance
is 93% slower than on kernel 4.4. Kernel 4.13 direct sync 4KB write
could only achieve 303KB/s while kernel 4.4 could achieve 4.5MB/s.
The VM is using ext4 filesystem and running on top of ZFS ZVOL on ZFS
RAID1 with virtio-scsi, qemu disk cache none, and qemu disk discard
enabled. The underlying physical disks are Samsung Enterprise SSD SM863a
480GB series.
The reason I need to run kernel 4.13 to mount CephFS Luminous with
kernel client. Hopefully CephFS Luminous kernel client will be back
ported to kernel 4.4 in the near future.
Is this from Ubuntu Xenial kernel 4.13 performance regression or from
Proxmox VE 5.1 kernel 4.13 virtio-scsi performance regression?
The test results:
##
# ubuntu xenial kernel 4.13. the direct synchronous write performance is 93%
slower than kernel 4.4
##
root@localhost:~# uname -a
Linux localhost 4.13.0-37-generic #42~16.04.1-Ubuntu SMP Wed Mar 7 16:03:28
UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
root@localhost:~# dd if=/dev/zero of=/mnt/test/test bs=4K count=256
oflag=direct,sync status=progress; rm /mnt/test/test
1048576 bytes (1.0 MB, 1.0 MiB) copied, 3.46369 s, 303 kB/s
##
# ubuntu xenial kernel 4.4. the direct synchronous write performance is 14x
faster than kernel 4.13
##
root@localhost:~# uname -a
Linux localhost 4.4.0-116-generic #140-Ubuntu SMP Mon Feb 12 21:23:04 UTC
2018 x86_64 x86_64 x86_64 GNU/Linux
root@localhost:~# dd if=/dev/zero of=/mnt/test/test bs=4K count=256
oflag=direct,sync status=progress; rm /mnt/test/test
1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.231176 s, 4.5 MB/s
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.13.0-37-generic 4.13.0-37.42~16.04.1
ProcVersionSignature: Ubuntu 4.13.0-37.42~16.04.1-generic 4.13.13
Uname: Linux 4.13.0-37-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
Date: Sun Mar 25 13:43:34 2018
InstallationDate: Installed on 2018-03-22 (2 days ago)
InstallationMedia: Ubuntu-Server 16.04.4 LTS "Xenial Xerus" - Release amd64
(20180228)
ProcEnviron:
TERM=screen-bce
PATH=(custom, no user)
XDG_RUNTIME_DIR=
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: linux-hwe
UpgradeStatus: No upgrade log present (probably fresh install)
---
AlsaDevices:
total 0
crw-rw 1 root audio 116, 1 May 7 22:23 seq
crw-rw 1 root audio 116, 33 May 7 22:23 timer
AplayDevices: Error: [Errno 2] No such file or directory
ApportVersion: 2.20.1-0ubuntu2.16
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq',
'/dev/snd/timer'] failed with exit code 1:
DistroRelease: Ubuntu 16.04
HibernationDevice: RESUME=/dev/mapper/localhost-swap
InstallationDate: Installed on 2018-03-22 (47 days ago)
InstallationMedia: Ubuntu-Server 16.04.4 LTS "Xenial Xerus" - Release amd64
(20180228)
IwConfig: Error: [Errno 2] No such file or directory
Lsusb:
Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: QEMU Standard PC (i440FX + PIIX, 1996)
Package: linux (not installed)
PciMultimedia:
ProcEnviron:
TERM=screen-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.13.0-39-generic
root=/dev/mapper/localhost-root ro
ProcVersionSignature: Ubuntu 4.13.0-39.44~16.04.1-generic 4.13.16
RelatedPackageVersions:
linux-restricted-modules-4.13.0-39-generic N/A
linux-backports-modules-4.13.0-39-generic N/A
linux-firmware 1.157.17
RfKill: Error: [Errno 2] No such file or directory
Tags: xenial
Uname: Linux 4.13.0-39-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:
_MarkForUpload: True
dmi.bios.date: 04/01/2014
dmi.bios.vendor: SeaBIOS
dmi.bios.version: rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-i440fx-2.11
dmi.modalias:
dmi:bvnSeaBIOS:bvrrel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org:bd04/01/2014:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-2.11:cvnQEMU:ct1:cvrpc-i440fx-2.11:
dmi.product.name: Standard PC (i440FX + PIIX, 1996)
dmi.product.version: pc-i440fx-2.11
dmi.sys.vendor: QEMU
+ ---
+ AlsaDevices:
+ total 0
+ crw-rw+ 1 root audio 116, 1 May 9 01:40 seq
+ crw-rw
