Bug 861934

Summary:	Severe btrfs performance issue (intermittent)
Product:	[Fedora] Fedora	Reporter:	Stephen Gallagher <sgallagh>
Component:	kernel	Assignee:	Zach Brown <zab>
Status:	CLOSED INSUFFICIENT_DATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	urgent	Docs Contact:
Priority:	unspecified
Version:	18	CC:	gansalmon, itamar, jonathan, josef, kernel-maint, madhu.chinakonda, sweil
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-07-01 14:01:53 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Stephen Gallagher 2012-10-01 11:58:23 UTC

Description of problem:
Often throughout the day, I will see spikes of I/O activity accompanied by 100% CPU use of one of 'btrfs-cleaner', 'btrfs-endio-wri' or 'btrfs-transacti'.

This will last anywhere from 5 seconds to upwards of two minutes, during which the rest of the system will be mostly unresponsive.

Version-Release number of selected component (if applicable):
kernel-3.6.0-0.rc7.git1.4.fc18.x86_64 (rebuilt in non-debug mode)

How reproducible:
Happens at least once an hour with no obvious trigger.

Steps to Reproduce:
1. See above
2.
3.
  
Actual results:
Very poor performance at random intervals.

Expected results:
The filesystem driver should not render the system useless

Additional info:
I rebuilt the kernel in non-debug mode to rule out that the performance issue was caused there.

With guidance, I am willing to perform debugging steps to identify the cause of this issue.

Additional hardware info: I am using an Intel solid-state disk, model SSDSA2MH080G1 (First-generation, no TRIM support).

Comment 1 Josef Bacik 2012-11-01 20:00:50 UTC

sysrq+w when the problem is happening will let me know what's going on and we can go from there.

Comment 2 Stephen Gallagher 2012-11-02 13:05:07 UTC

Is there a trick to getting SysRq to work from Cinnamon? I've tried alt-SysRq-w, ctrl-alt-SysRq-w (on my external keyboard) and the same plus Fn on my laptop keyboard. I've seen no indication that this has done anything except occasionally taking screenshots.

Comment 3 Josef Bacik 2012-11-02 13:14:48 UTC

open a terminal and echo w > /proc/sysrq-trigger.

Comment 4 Dave Jones 2013-05-15 18:57:15 UTC

any progress on this ? still reproducible ?

Comment 5 Josh Boyer 2013-07-01 14:01:53 UTC

This bug is being closed with INSUFFICIENT_DATA as there has not been a response in 2 weeks. If you are still experiencing this issue, please reopen and attach the relevant data from the latest kernel you are running and any data that might have been requested previously.