Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [patch,rfc v2] ext3/4: enhance fsync performance when using cfq | Date | Thu, 08 Apr 2010 10:25:50 -0400 |
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Vivek Goyal <vgoyal@redhat.com> writes:
> On Thu, Apr 08, 2010 at 10:03:24AM -0400, Jeff Moyer wrote: >> Which actually brings up the question of whether this needs some >> knowledge of whether the journal is on the same device as the file >> system! In such a case, we need not yield. I think I'll stick my head >> in the sand for this one. ;-) > > Jeff even if journal is not on same device, what harm yielding could do? > Anyway there is no IO on that queue and we are idling. Only side affect is > that yielding process could lose a bit if after fsync it immediately submits > more IO. Because this process has yielded it slice, it is back in the queue > instead of doing more IO in the current slice immediately.
What happens if the journal is on a super fast device, and finishes up very quickly allowing our process to initiate more I/O within the idle window?
Cheers, Jeff
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