On Thu, Apr 26 2007, Alan D. Brunelle wrote: > Jens Axboe wrote: > >On Wed, Apr 25 2007, Jens Axboe wrote: > >>On Wed, Apr 25 2007, Jens Axboe wrote: > >>>On Wed, Apr 25 2007, Alan D. Brunelle wrote: > >>>>Hi Jens - > >>>> > >>>>The attached patch speeds it up even more - I'm finding a >9% reduction > >>>>in %system with no loss in IO performance. This just sets the cached > >>>>element when the first is looked for. > >>>Interesting, good thinking. It should not change the IO pattern, as the > >>>end result should be the same. Thanks Alan, will commit! > >>> > >>>I'll give elevator.c the same treatment, should be even more beneficial. > >>>Stay tuned for a test patch. > >>Something like this, totally untested (it compiles). I initially wanted > >>to fold the cfq addon into the elevator.h provided implementation, but > >>that requires more extensive changes. Given how little code it is, I > >>think I'll keep them seperate. > > > >Booted, seems to work fine for me. In a null ended IO test, I get about > >a 1-2% speedup for a single queue of depth 64 using libaio. So it's > >definitely worth it, will commit. > > > After longer runs last night, I think the patched elevator code /does/ > help (albeit ever so slightly - about 0.6% performance improvement at a > 1.1% %system overhead). > > rkB_s %system Kernel > --------- ------- ---------------------------------------------------- > 1022942.2 3.69 Original patch + fix to cfq_rb_first > 1029087.0 3.73 This patch stream (including fixes to elevator code)
Ah good, thanks for testing! It's all in the cfq branch now. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
