Swap causes 100% IOWait and renders system useless

Bug #410096 reported by Kristopher Ives
24
This bug affects 3 people
Affects Status Importance Assigned to Milestone
Mozilla Firefox
Invalid
Critical
firefox-3.0 (Ubuntu)
Invalid
Undecided
Unassigned
firefox-3.5 (Ubuntu)
Invalid
High
Unassigned

Bug Description

Every once in a while my system becomes completely absorbed by IOWait, which I believe is when swapping occurs. I have 2GB RAM and it rarely uses more than 1GB of RAM. I have tried changing vm.swappiness to 0 without any success as well.

I would love to provide a `pidstat -d` output or similar, but seriously the system becomes completely unresponsive for long periods of time. It displays mouse animations and continues to play musing in Pandora or Rhythmbox (although it may stutter) and when I regain control of the system there are no processes with unreasonable statistics. I don't believe it's related to update-apt-xapian-index, which I think everyone hates and is poorly designed. I have tried JFS and XFS, and this hasn't made a difference.

Anoyne care to actually find out what is causing this? IOWait related issues are a huge problem and nobody seems to care. Any debugging tips would be much appreciated, but remember that I cannot execute anything when this is happeneing.

I suspect that the kernel page flushing (kpdflush?) may be the cause. Anyone think it would help to put swap as a file on the partition for better IO scheduling?

Thanks!

Revision history for this message
Kristopher Ives (krisives) wrote :

When this happened I ran `pidstat -d` and was able to `killall -9 firefox` and it solved the problem! See the attached output if you're interested.

Revision history for this message
In , Kristopher Ives (krisives) wrote :

User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.13) Gecko/2009080315 Ubuntu/9.04 (jaunty) Firefox/3.0.13
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.13) Gecko/2009080315 Ubuntu/9.04 (jaunty) Firefox/3.0.13

In Ubuntu 9.04 I would get huge amounts of IOwait that makes the system very unresponsive and pretty much impossible to do anything with. It seems to be related to Firefox, since if I `killall -9 firefox` when this is happening it immediately stops, and `pidstat -d` outputs:

02:51:38 PM 3636 6.13 2.16 0.72 firefox

I've tried this with multiple file systems (Ext3, JFS, and XFS) without a difference in the behaviour.

Reproducible: Couldn't Reproduce

Steps to Reproduce:
I don't know how I can reproduce this. Originally I thought it was related to swap usage, but I've ran into this with my swap disabled and nowhere near my 2GB RAM limit.

Original bug started from this Luanchpad report:

https://bugs.launchpad.net/ubuntu/+bug/410096

Revision history for this message
Kristopher Ives (krisives) wrote :
Revision history for this message
In , Sylvain Pasche (sylvain-pasche) wrote :

You could try setting toolkit.storage.synchronous to 0 in about:config and report if that helps (warning, this can lead to file corruption if your system crashes after having set that pref, so you should backup your profile).

Another thing to check is to use the strace tool to see what Firefox is doing when the system is slow (example: strace -f -tt -T -p <pid of firefox-bin>). Please report here with your findings.

Revision history for this message
In , Sylvain Pasche (sylvain-pasche) wrote :

I forgot, before that you should try with Firefox 3.5 or 3.6 and see if the issue still happens.

Jorge Castro (jorge)
affects: ubuntu → firefox (Ubuntu)
Changed in firefox:
status: Unknown → New
Revision history for this message
Micah Gersten (micahg) wrote :

Moving to Firefox 3.0 package

affects: firefox (Ubuntu) → firefox-3.0 (Ubuntu)
Changed in firefox-3.0 (Ubuntu):
importance: Undecided → High
status: New → Triaged
Revision history for this message
John Vivirito (gnomefreak) wrote :

Changed Firefox version to be Firefox-3.5 as Firefox-3.0 has reached EOL.
This bug hasn't had any reply in a long time can you please confirm if this happens with latest version of Firefox-3.5 from our repos.

affects: firefox-3.0 (Ubuntu) → firefox-3.5 (Ubuntu)
Revision history for this message
John Vivirito (gnomefreak) wrote :

Sorry but i found out a little while ago 3.0.18 will be released.

Changed in firefox-3.0 (Ubuntu):
status: New → Triaged
Changed in firefox:
importance: Unknown → Critical
Revision history for this message
Petr A. Sokolnikov (petr-sokolnikov) wrote :

The same bug in Firefox 3.6.13 in Ubuntu 10.10. How can I fix it?

Revision history for this message
In , Tyler Downer (tyler-downer) wrote :

Reporter, are you still seeing this issue with Firefox 3.6.13 or later in safe mode or a fresh profile? If not, please close. These links can help you in your testing.
http://support.mozilla.com/kb/Safe+Mode
http://support.mozilla.com/kb/Managing+profiles

Revision history for this message
In , Kristopher Ives (krisives) wrote : Re: [Bug 410096]

I am using 3.6 now and can't re-test. Sorry.

On Tue, Feb 1, 2011 at 10:35 PM, Tyler Downer <email address hidden>wrote:

> Reporter, are you still seeing this issue with Firefox 3.6.13 or later in
> safe mode or a fresh profile? If not, please close. These links can help you
> in your testing.
> http://support.mozilla.com/kb/Safe+Mode
> http://support.mozilla.com/kb/Managing+profiles
>
> --
> You received this bug notification because you are a direct subscriber
> of the bug.
> https://bugs.launchpad.net/bugs/410096
>
> Title:
> Swap causes 100% IOWait and renders system useless
>
> Status in The Mozilla Firefox Browser:
> New
> Status in “firefox-3.0” package in Ubuntu:
> Triaged
> Status in “firefox-3.5” package in Ubuntu:
> Triaged
>
> Bug description:
> Every once in a while my system becomes completely absorbed by IOWait,
> which I believe is when swapping occurs. I have 2GB RAM and it rarely
> uses more than 1GB of RAM. I have tried changing vm.swappiness to 0
> without any success as well.
>
> I would love to provide a `pidstat -d` output or similar, but
> seriously the system becomes completely unresponsive for long periods
> of time. It displays mouse animations and continues to play musing in
> Pandora or Rhythmbox (although it may stutter) and when I regain
> control of the system there are no processes with unreasonable
> statistics. I don't believe it's related to update-apt-xapian-index,
> which I think everyone hates and is poorly designed. I have tried JFS
> and XFS, and this hasn't made a difference.
>
> Anoyne care to actually find out what is causing this? IOWait related
> issues are a huge problem and nobody seems to care. Any debugging tips
> would be much appreciated, but remember that I cannot execute anything
> when this is happeneing.
>
> I suspect that the kernel page flushing (kpdflush?) may be the cause.
> Anyone think it would help to put swap as a file on the partition for
> better IO scheduling?
>
> Thanks!
>
> To unsubscribe from this bug, go to:
> https://bugs.launchpad.net/firefox/+bug/410096/+subscribe
>

Changed in firefox:
status: New → Invalid
Adam Porter (alphapapa)
Changed in firefox-3.5 (Ubuntu):
status: Triaged → Incomplete
Revision history for this message
Phillip Susi (psusi) wrote :

Since neither firefox-3.0 nor firefox-3.5 are supported any longer, and the upstream bug was closed as incomplete, and this report is incomplete, I am closing it.

Changed in firefox-3.5 (Ubuntu):
status: Incomplete → Invalid
Changed in firefox-3.0 (Ubuntu):
status: Triaged → Invalid
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