btrfs with discard option has terrible performance

Bug #797075 reported by Ketil Malde
62
This bug affects 11 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Confirmed
Undecided
Unassigned

Bug Description

Enabling 'discard' for btrfs on an SSD results in a substantial performance degradation, possibly related to fsync(). This is very noticable when running 'apt-get upgrade', and the test suggested in the link below went from 12 seconds without discard to 45 seconds with discard enabled.

http://lists-archives.org/linux-kernel/27396958-btrfs-and-apt-package-manager-in-ubuntu-discard-stalls.html

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: linux-image (not installed)
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: STAC92xx Analog [STAC92xx Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ketil 1710 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xd4500000 irq 45'
   Mixer name : 'Intel Cantiga HDMI'
   Components : 'HDA:111d7605,103c3663,00100402 HDA:80862802,80860101,00100000'
   Controls : 18
   Simple ctrls : 10
Date: Tue Jun 14 09:20:35 2011
HibernationDevice: RESUME=UUID=ad4c20c6-5224-457d-9cd8-868767fd928c
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
MachineType: Hewlett-Packard HP Pavilion dm1 Notebook PC
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/zsh
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-2.6.38-8-generic root=UUID=2a634684-4d1a-4822-8950-c1446eb3585b ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-2.6.38-8-generic N/A
 linux-backports-modules-2.6.38-8-generic N/A
 linux-firmware 1.52
SourcePackage: linux
UpgradeStatus: Upgraded to natty on 2011-05-04 (40 days ago)
dmi.bios.date: 09/03/2009
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.02
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 3663
dmi.board.vendor: Quanta
dmi.board.version: 49.0A
dmi.chassis.type: 10
dmi.chassis.vendor: Quanta
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.02:bd09/03/2009:svnHewlett-Packard:pnHPPaviliondm1NotebookPC:pvr0392100000201B00000320000:rvnQuanta:rn3663:rvr49.0A:cvnQuanta:ct10:cvrN/A:
dmi.product.name: HP Pavilion dm1 Notebook PC
dmi.product.version: 0392100000201B00000320000
dmi.sys.vendor: Hewlett-Packard

Revision history for this message
Ketil Malde (ketil-ii) wrote :
Brad Figg (brad-figg)
Changed in linux (Ubuntu):
status: New → Confirmed
To post a comment you must log in.
This report contains Public information  
Everyone can see this information.

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.