On Tue, Jul 19, 2011 at 09:36:33AM +0200, Jörn Engel wrote: > On Tue, 19 July 2011 12:41:38 +1000, Dave Chinner wrote: > > On Mon, Jul 18, 2011 at 01:40:36PM +0200, Jörn Engel wrote: > > > On Mon, 18 July 2011 20:57:49 +1000, Dave Chinner wrote: > > > > On Mon, Jul 18, 2011 at 09:53:39AM +0200, Jörn Engel wrote: > > > > > On Mon, 18 July 2011 09:32:52 +1000, Dave Chinner wrote: > > > > > > On Sun, Jul 17, 2011 at 06:05:01PM +0200, Jörn Engel wrote: > > > > > > > > > > > xfs: > > > > > > > ==== > > > > > > > seqrd 1 2 4 8 16 32 64 128 > > > > > > > 16384 4698 4424 4397 4402 4394 4398 4642 4679 > > > > > > > 8192 6234 5827 5797 5801 5795 6114 5793 5812 > > > > > > > 4096 9100 8835 8882 8896 8874 8890 8910 8906 > > > > > > > 2048 14922 14391 14259 14248 14264 14264 14269 14273 > > > > > > > 1024 23853 22690 22329 22362 22338 22277 22240 22301 > > > > > > > 512 37353 33990 33292 33332 33306 33296 33224 33271 > > > > > seqrd 1 2 4 8 16 32 64 128 > > > 16384 4542 8311 15738 28955 38273 36644 38530 38527 > > > 8192 6000 10413 19208 33878 65927 76906 77083 77102 > > > 4096 8931 14971 24794 44223 83512 144867 147581 150702 > > > 2048 14375 23489 34364 56887 103053 192662 307167 309222 > > > 1024 21647 36022 49649 77163 132886 243296 421389 497581 > > > 512 31832 61257 79545 108782 176341 303836 517814 584741 > > > > > What bothers me a bit is that the single-threaded numbers took such a > > > noticeable hit... > > > > Is it reproducable? I did notice quite a bit of run-to-run variation > > in the numbers I ran. For single threaded numbers, they appear to be > > in the order of +/-100 ops @ 16k block size. > > Ime the numbers are stable within about 10%. And given that out of > six measurements every single one is a regression, I would feel > confident to bet a beverage without further measurements. Regression > is 3.4%, 3.9%, 1.9%, 3.8%, 10% and 17% respectively, so the effect > appears to be more visible with smaller block numbers as well. Only thing I can think of then is that taking the lock shared is more expensive than taking it exclusive. Otherwise there is little change to the code path.... /me shrugs and cares not all that much right now Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
