Hi Paul, FYI, this improves will-it-scale/open1 throughput. git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2014.04.14a commit b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 ("sched,rcu: Make cond_resched() report RCU quiescent states") ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 563496 ~ 0% +3.1% 581059 ~ 0% nhm4/micro/will-it-scale/open1 563496 ~ 0% +3.1% 581059 ~ 0% TOTAL will-it-scale.per_thread_ops ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 756894 ~ 0% +2.8% 778452 ~ 0% nhm4/micro/will-it-scale/open1 756894 ~ 0% +2.8% 778452 ~ 0% TOTAL will-it-scale.per_process_ops ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 0.57 ~ 0% -2.7% 0.55 ~ 0% nhm4/micro/will-it-scale/open1 0.57 ~ 0% -2.7% 0.55 ~ 0% TOTAL will-it-scale.scalability ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 346764 ~ 2% -74.0% 90164 ~ 1% nhm4/micro/will-it-scale/open1 346764 ~ 2% -74.0% 90164 ~ 1% TOTAL slabinfo.kmalloc-256.active_objs ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 10837 ~ 2% -73.9% 2824 ~ 1% nhm4/micro/will-it-scale/open1 10837 ~ 2% -73.9% 2824 ~ 1% TOTAL slabinfo.kmalloc-256.active_slabs ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 10837 ~ 2% -73.9% 2824 ~ 1% nhm4/micro/will-it-scale/open1 10837 ~ 2% -73.9% 2824 ~ 1% TOTAL slabinfo.kmalloc-256.num_slabs ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 346821 ~ 2% -73.9% 90393 ~ 1% nhm4/micro/will-it-scale/open1 346821 ~ 2% -73.9% 90393 ~ 1% TOTAL slabinfo.kmalloc-256.num_objs ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 105961 ~ 1% -63.0% 39153 ~ 1% nhm4/micro/will-it-scale/open1 105961 ~ 1% -63.0% 39153 ~ 1% TOTAL meminfo.SUnreclaim ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 26432 ~ 1% -62.9% 9814 ~ 1% nhm4/micro/will-it-scale/open1 26432 ~ 1% -62.9% 9814 ~ 1% TOTAL proc-vmstat.nr_slab_unreclaimable ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 50298 ~ 0% +194.3% 148011 ~ 0% nhm4/micro/will-it-scale/open1 37020 ~ 0% +42.6% 52798 ~ 1% nhm4/micro/will-it-scale/signal1 87318 ~ 0% +130.0% 200809 ~ 0% TOTAL softirqs.RCU ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 140354 ~ 1% -47.6% 73490 ~ 0% nhm4/micro/will-it-scale/open1 140354 ~ 1% -47.6% 73490 ~ 0% TOTAL meminfo.Slab ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 77391 ~ 1% -46.7% 41235 ~ 2% nhm4/micro/will-it-scale/signal1 77391 ~ 1% -46.7% 41235 ~ 2% TOTAL cpuidle.C6-NHM.usage ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 19871 ~ 2% -37.6% 12397 ~ 2% nhm4/micro/will-it-scale/open1 18497 ~ 1% -37.5% 11556 ~ 1% nhm4/micro/will-it-scale/signal1 38368 ~ 2% -37.6% 23954 ~ 2% TOTAL softirqs.SCHED ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 1.24 ~ 4% -35.4% 0.80 ~ 3% nhm4/micro/will-it-scale/open1 1.24 ~ 4% -35.4% 0.80 ~ 3% TOTAL perf-profile.cpu-cycles.do_notify_resume.int_signal.close ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 1.43 ~ 4% +41.9% 2.03 ~ 4% nhm4/micro/will-it-scale/open1 1.43 ~ 4% +41.9% 2.03 ~ 4% TOTAL perf-profile.cpu-cycles.rcu_process_callbacks.__do_softirq.irq_exit.smp_apic_timer_interrupt.apic_timer_interrupt ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 1.27 ~ 3% -30.0% 0.89 ~ 6% nhm4/micro/will-it-scale/open1 1.27 ~ 3% -30.0% 0.89 ~ 6% TOTAL perf-profile.cpu-cycles.setup_object.isra.46.new_slab.__slab_alloc.kmem_cache_alloc.get_empty_filp ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 1.54 ~ 7% +35.6% 2.09 ~ 8% nhm4/micro/will-it-scale/open1 1.54 ~ 7% +35.6% 2.09 ~ 8% TOTAL perf-profile.cpu-cycles.kmem_cache_alloc.getname_flags.getname.do_sys_open.sys_open ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 4.21 ~ 2% -29.1% 2.98 ~ 3% nhm4/micro/will-it-scale/open1 4.21 ~ 2% -29.1% 2.98 ~ 3% TOTAL perf-profile.cpu-cycles.link_path_walk.path_openat.do_filp_open.do_sys_open.sys_open ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 1.37 ~ 4% -23.1% 1.05 ~ 7% nhm4/micro/will-it-scale/open1 1.37 ~ 4% -23.1% 1.05 ~ 7% TOTAL perf-profile.cpu-cycles.__d_lookup_rcu.lookup_fast.link_path_walk.path_openat.do_filp_open ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 0.88 ~17% +29.1% 1.14 ~ 9% nhm4/micro/will-it-scale/open1 0.88 ~17% +29.1% 1.14 ~ 9% TOTAL perf-profile.cpu-cycles.path_init.path_openat.do_filp_open.do_sys_open.sys_open ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 0.67 ~16% +33.6% 0.90 ~10% nhm4/micro/will-it-scale/signal1 0.67 ~16% +33.6% 0.90 ~10% TOTAL perf-profile.cpu-cycles.restore_sigcontext.sys_rt_sigreturn.stub_rt_sigreturn.raise ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 3.19 ~ 1% +17.4% 3.74 ~ 5% nhm4/micro/will-it-scale/open1 3.19 ~ 1% +17.4% 3.74 ~ 5% TOTAL perf-profile.cpu-cycles.file_free_rcu.rcu_process_callbacks.__do_softirq.irq_exit.smp_apic_timer_interrupt ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 4329 ~ 7% +15.2% 4986 ~ 5% nhm4/micro/will-it-scale/open1 4329 ~ 7% +15.2% 4986 ~ 5% TOTAL slabinfo.vm_area_struct.active_objs ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 2536 ~ 1% -75.8% 614 ~ 9% nhm4/micro/will-it-scale/open1 2536 ~ 1% -75.8% 614 ~ 9% TOTAL time.involuntary_context_switches ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 32593 ~ 1% -62.1% 12349 ~ 2% nhm4/micro/will-it-scale/signal1 32593 ~ 1% -62.1% 12349 ~ 2% TOTAL interrupts.0:IO-APIC-edge.timer ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 4374 ~14% +124.7% 9830 ~ 8% nhm4/micro/will-it-scale/open1 2559 ~ 2% +20.3% 3078 ~ 3% nhm4/micro/will-it-scale/signal1 6934 ~ 9% +86.2% 12908 ~ 7% TOTAL interrupts.RES ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 490 ~ 1% -37.3% 307 ~ 1% nhm4/micro/will-it-scale/signal1 490 ~ 1% -37.3% 307 ~ 1% TOTAL vmstat.system.cs ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 1639 ~ 0% -8.8% 1495 ~ 0% nhm4/micro/will-it-scale/signal1 1639 ~ 0% -8.8% 1495 ~ 0% TOTAL vmstat.system.in ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 419046 ~ 0% -1.5% 412661 ~ 0% nhm4/micro/will-it-scale/open1 400635 ~ 0% -5.9% 376866 ~ 0% nhm4/micro/will-it-scale/signal1 819681 ~ 0% -3.7% 789527 ~ 0% TOTAL interrupts.LOC Legend: ~XX% - stddev percent [+-]XX% - change percent time.involuntary_context_switches 3500 ++------------------------------------------------------------------+ | .*.. | 3000 ++ .*. *..*.. .*..*.. .*.. | *..*..*..*. *. * | | *..*.. .*.. .*..* | 2500 ++ *..*. *..*. | | | 2000 ++ | | | 1500 ++ | | | | | 1000 ++ | | O O O O O O O O O 500 O+-O-----------O--O--O--O--------O-O--O--O--O--O--------O-----O--O--+ [*] bisect-good sample [O] bisect-bad sample Thanks, Fengguang