On Sat, 2013-06-01 at 21:02 +0200, Manfred Spraul wrote: > Hi Rik, > > I finally managed to get EFI boot, i.e. I'm now able to test on my i3 > (2core+HT). > > With semscale (i.e.: just overhead, perform semop=0 operations), the > scalability from 1 to 2 cores is good, but not linear: > # semscale 10 | grep "interleave 2" > > Cpus 1, interleave 2 delay 0: 35502103 in 10 secs > > Cpus 2, interleave 2 delay 0: 53990954 in 10 secs > --- > +53% when adding the 2nd core > (interleave 2 to force to use different cores) > > Did you consider moving sem_otime into the individual semaphores? > I did that (gross patch attached), and the performance is significantly > better: > > # semscale 10 | grep "interleave 2" > Cpus 1, interleave 2 delay 0: 35585634 in 10 secs > Cpus 2, interleave 2 delay 0: 70410230 in 10 secs > --- > +99% scalability when adding the 2nd core > > Unfortunately I won't be able to read my mails next week, but the effect > was too significant not to share it immediately.
64 core box. Previous numbers: vogelweide:/abuild/mike/:[0]# uname -r 3.8.13-rt9-rtm vogelweide:/abuild/mike/:[0]# ./semop-multi 256 64 cpus 64, threads: 256, semaphores: 64, test duration: 30 secs total operations: 33553800, ops/sec 1118460 New numbers: vogelweide:/abuild/mike/:[0]# !./semop-multi ./semop-multi 256 64 cpus 64, threads: 256, semaphores: 64, test duration: 30 secs total operations: 129474934, ops/sec 4315831 But, box rcu stalled on me. It's looking like the scalability patches are a bit racy rcu wise in an -rt kernel (oh dear). So, build as plain old PREEMPT again, eliminate -rt funnies. Previous numbers: vogelweide:/abuild/mike/:[0]# ./semop-multi 256 64 cpus 64, threads: 256, semaphores: 64, test duration: 30 secs total operations: 22053968, ops/sec 735132 vogelweide:/abuild/mike/:[0]# ./osim 64 256 1000000 0 0 osim <sems> <tasks> <loops> <busy-in> <busy-out> osim: using a semaphore array with 64 semaphores. osim: using 256 tasks. osim: each thread loops 3907 times osim: each thread busyloops 0 loops outside and 0 loops inside. total execution time: 1.858765 seconds for 1000192 loops per loop execution time: 1.858 usec New numbers: vogelweide:/abuild/mike/:[0]# !./semop ./semop-multi 256 64 cpus 64, threads: 256, semaphores: 64, test duration: 30 secs total operations: 45521478, ops/sec 1517382 vogelweide:/abuild/mike/:[0]# !./osim ./osim 64 256 1000000 0 0 osim <sems> <tasks> <loops> <busy-in> <busy-out> osim: using a semaphore array with 64 semaphores. osim: using 256 tasks. osim: each thread loops 3907 times osim: each thread busyloops 0 loops outside and 0 loops inside. total execution time: 0.350682 seconds for 1000192 loops per loop execution time: 0.350 usec (1.8->0.3?.. box, you ain't a race horse, you're a plow horse) vogelweide:/abuild/mike/:[0]# ./osim 64 256 1000000 0 0 osim <sems> <tasks> <loops> <busy-in> <busy-out> osim: using a semaphore array with 64 semaphores. osim: using 256 tasks. osim: each thread loops 3907 times osim: each thread busyloops 0 loops outside and 0 loops inside. total execution time: 0.276405 seconds for 1000192 loops per loop execution time: 0.276 usec vogelweide:/abuild/mike/:[0]# ./osim 64 256 1000000 0 0 osim <sems> <tasks> <loops> <busy-in> <busy-out> osim: using a semaphore array with 64 semaphores. osim: using 256 tasks. osim: each thread loops 3907 times osim: each thread busyloops 0 loops outside and 0 loops inside. total execution time: 0.370041 seconds for 1000192 loops per loop execution time: 0.369 usec vogelweide:/abuild/mike/:[0]# ./osim 64 256 1000000 0 0 osim <sems> <tasks> <loops> <busy-in> <busy-out> osim: using a semaphore array with 64 semaphores. osim: using 256 tasks. osim: each thread loops 3907 times osim: each thread busyloops 0 loops outside and 0 loops inside. total execution time: 0.502396 seconds for 1000192 loops per loop execution time: 0.502 usec (runtime) vogelweide:/abuild/mike/:[0]# ./osim 64 256 10000000 0 0 osim <sems> <tasks> <loops> <busy-in> <busy-out> osim: using a semaphore array with 64 semaphores. osim: using 256 tasks. osim: each thread loops 39063 times osim: each thread busyloops 0 loops outside and 0 loops inside. total execution time: 3.354423 seconds for 10000128 loops per loop execution time: 0.335 usec vogelweide:/abuild/mike/:[0]# ./osim 64 256 100000000 0 0 osim <sems> <tasks> <loops> <busy-in> <busy-out> osim: using a semaphore array with 64 semaphores. osim: using 256 tasks. osim: each thread loops 390625 times osim: each thread busyloops 0 loops outside and 0 loops inside. total execution time: 41.180479 seconds for 100000000 loops per loop execution time: 0.411 usec Box likes your idea. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
