Re: [ck] Re: [announce] [patch] Voluntary Kernel Preemption Patch

Con Kolivas
2004-07-11T14:29:59Z

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Con Kolivas wrote:
> Ingo Molnar wrote:
>
>> * Con Kolivas <kernel@kolivas.org> wrote:
>>
>>
>>> Ooops forgot to mention this was running reiserFS 3.6 on software
>>> raid0 2x IDE with cfq elevator.
>>
>>
>>
>> ok, reiserfs (and all journalling fs's) definitely need a look - as you
>> can see from the ext3 mods in the patch. Any chance you could try ext3
>> based tests? Those are the closest to my setups.
>>
>
> Ok I've done one better than that ;) I had wli help make some
> instrumentation for me to help find the remaining non preemptible kernel
> portions and set the cutoff to 2ms. Here is what I found:
>
> 7ms non-preemptible critical section violated 2 ms preempt threshold
> starting at reiserfs_sync_fs+0x2d/0xc2 and ending at reiser
> fs_lookup+0xe2/0x221
>
> 9ms non-preemptible critical section violated 2 ms preempt threshold
> starting at reiserfs_dirty_inode+0x37/0x10e and ending at r
> eiserfs_dirty_inode+0xb0/0x10e
>
>
> These seem to be the two offenders. Hope this helps.

Oh and here are two different ones:

5ms non-preemptible critical section violated 2 ms preempt threshold
starting at add_wait_queue+0x21/0x82 and ending at add_wait
_queue+0x4a/0x82

3ms non-preemptible critical section violated 2 ms preempt threshold
starting at exit_mmap+0x1c/0x188 and ending at exit_mmap+0x
118/0x188

Con

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