I/O Scheduling results in poor responsiveness

[Nathan Grennan]

Nathan Grennan wrote:
>
>  I figured it all out. The main issue was my use of a Firefox 3.0 
> nightly. From Firefox 3.0b3 on Firefox is very fsync happy. As in ever 
> time you load a page it fsync about eight times. Do things in the 
> middle of a big write and performance goes all to hell. I have filed a 
> bug upstream, https://bugzilla.mozilla.org/show_bug.cgi?id=421482 .
>
>  I ran across this idea by reading, http://kerneltrap.org/node/14148 . 
> The first e-mail from Ingo as a reply to another one of his earlier 
> e-mails mentions a case a lot like mine. Quad-Core, 4gb ram, and 30 
> second pauses in vim. He mentions vim uses fsync. He mentions an 
> option, but it isn't good enough. You have to also change set 
> swapsync, like below.
>
> I then straced vim and found any hiccups in the output were directly 
> related to when vim ran fsync. I set the options, and the problem 
> seemed to go away.
>
> Finally I turned to Firefox 3.0 nightly, and straced it. I found the 
> problem. I then went back to Firefox 2.0.0.12, and straced it. I found 
> it didn't have the same problem. So as nice as Firefox 3.0b3 or later 
> is, it is a recipe for unhappiness.
>
> set swapsync=sync
> set nofsync
>
>  But this is just a symptom of a bigger problem. As the Kernel Trap 
> url above mentions, ext3 + fsync = crappiness. So my next step will be 
> to talk to the right developers, learn as much as possible, and see if 
> a solution can be found. Otherwise I may completely give up on ext3 
> and move to another filesystem.
>
  The latest news is that this is most likely, because of Firefox 3.0b3+ 
use of sqlite. There was already another bug abotu poor zoom performance 
which relates to sqlite.

https://bugzilla.mozilla.org/show_bug.cgi?id=417732