* [sched,rcu] b84c4e08143: +3.1% will-it-scale.per_thread_ops
@ 2014-04-17 4:03 Fengguang Wu
2014-04-17 13:55 ` Paul E. McKenney
0 siblings, 1 reply; 4+ messages in thread
From: Fengguang Wu @ 2014-04-17 4:03 UTC (permalink / raw)
To: Paul E. McKenney; +Cc: LKML, lkp
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
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [sched,rcu] b84c4e08143: +3.1% will-it-scale.per_thread_ops 2014-04-17 4:03 [sched,rcu] b84c4e08143: +3.1% will-it-scale.per_thread_ops Fengguang Wu @ 2014-04-17 13:55 ` Paul E. McKenney 2014-04-19 8:11 ` Fengguang Wu 0 siblings, 1 reply; 4+ messages in thread From: Paul E. McKenney @ 2014-04-17 13:55 UTC (permalink / raw) To: Fengguang Wu; +Cc: LKML, lkp On Thu, Apr 17, 2014 at 12:03:53PM +0800, Fengguang Wu wrote: > Hi Paul, > > FYI, this improves will-it-scale/open1 throughput. Cool! Not a planned benefit, but I will take it. ;-) > 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") But how should I read the data below? I see lots of positive percentages and lots of negative percentages for the delta, and all near zero for standard deviation. Is the overall improvement an average of these or some such? What is being measured? > 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 So the good case increases involuntary context switches, but helps something else? Or does the benefit stem from increased involuntary context switches and thus less time spinning or some such? Thanx, Paul > Thanks, > Fengguang > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [sched,rcu] b84c4e08143: +3.1% will-it-scale.per_thread_ops 2014-04-17 13:55 ` Paul E. McKenney @ 2014-04-19 8:11 ` Fengguang Wu 2014-04-22 1:50 ` Paul E. McKenney 0 siblings, 1 reply; 4+ messages in thread From: Fengguang Wu @ 2014-04-19 8:11 UTC (permalink / raw) To: Paul E. McKenney; +Cc: LKML, lkp On Thu, Apr 17, 2014 at 06:55:03AM -0700, Paul E. McKenney wrote: > On Thu, Apr 17, 2014 at 12:03:53PM +0800, Fengguang Wu wrote: > > Hi Paul, > > > > FYI, this improves will-it-scale/open1 throughput. > > Cool! Not a planned benefit, but I will take it. ;-) > > > 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") > > But how should I read the data below? I see lots of positive percentages > and lots of negative percentages for the delta, and all near zero for > standard deviation. Is the overall improvement an average of these or > some such? What is being measured? There are a lot of things being measured, which are shown after each "TOTAL". For example, to get an overview of the report: grep "TOTAL" this_email 563496 ~ 0% +3.1% 581059 ~ 0% TOTAL will-it-scale.per_thread_ops 756894 ~ 0% +2.8% 778452 ~ 0% TOTAL will-it-scale.per_process_ops 0.57 ~ 0% -2.7% 0.55 ~ 0% TOTAL will-it-scale.scalability 346764 ~ 2% -74.0% 90164 ~ 1% TOTAL slabinfo.kmalloc-256.active_objs 10837 ~ 2% -73.9% 2824 ~ 1% TOTAL slabinfo.kmalloc-256.active_slabs 10837 ~ 2% -73.9% 2824 ~ 1% TOTAL slabinfo.kmalloc-256.num_slabs 346821 ~ 2% -73.9% 90393 ~ 1% TOTAL slabinfo.kmalloc-256.num_objs 105961 ~ 1% -63.0% 39153 ~ 1% TOTAL meminfo.SUnreclaim 26432 ~ 1% -62.9% 9814 ~ 1% TOTAL proc-vmstat.nr_slab_unreclaimable 87318 ~ 0% +130.0% 200809 ~ 0% TOTAL softirqs.RCU 140354 ~ 1% -47.6% 73490 ~ 0% TOTAL meminfo.Slab 77391 ~ 1% -46.7% 41235 ~ 2% TOTAL cpuidle.C6-NHM.usage 38368 ~ 2% -37.6% 23954 ~ 2% TOTAL softirqs.SCHED 1.24 ~ 4% -35.4% 0.80 ~ 3% TOTAL perf-profile.cpu-cycles.do_notify_resume.int_signal.close 1.43 ~ 4% +41.9% 2.03 ~ 4% TOTAL perf-profile.cpu-cycles.rcu_process_callbacks.__do_softirq.irq_exit.smp_apic_timer_in rupt.apic_timer_interrupt 1.27 ~ 3% -30.0% 0.89 ~ 6% TOTAL perf-profile.cpu-cycles.setup_object.isra.46.new_slab.__slab_alloc.kmem_cache_alloc.g empty_filp 1.54 ~ 7% +35.6% 2.09 ~ 8% TOTAL perf-profile.cpu-cycles.kmem_cache_alloc.getname_flags.getname.do_sys_open.sys_open 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 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 en 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 0.67 ~16% +33.6% 0.90 ~10% TOTAL perf-profile.cpu-cycles.restore_sigcontext.sys_rt_sigreturn.stub_rt_sigreturn.raise 3.19 ~ 1% +17.4% 3.74 ~ 5% TOTAL perf-profile.cpu-cycles.file_free_rcu.rcu_process_callbacks.__do_softirq.irq_exit.smp ic_timer_interrupt 4329 ~ 7% +15.2% 4986 ~ 5% TOTAL slabinfo.vm_area_struct.active_objs 2536 ~ 1% -75.8% 614 ~ 9% TOTAL time.involuntary_context_switches 32593 ~ 1% -62.1% 12349 ~ 2% TOTAL interrupts.0:IO-APIC-edge.timer 6934 ~ 9% +86.2% 12908 ~ 7% TOTAL interrupts.RES 490 ~ 1% -37.3% 307 ~ 1% TOTAL vmstat.system.cs 1639 ~ 0% -8.8% 1495 ~ 0% TOTAL vmstat.system.in 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 > > So the good case increases involuntary context switches, but helps something > else? Or does the benefit stem from increased involuntary context switches > and thus less time spinning or some such? In bisect POV, branch BASE is good and HEAD is bad. Which has nothing to do with the improvement/regression in performance POV. Here the HEAD(bisect bad) commit has less involuntary_context_switches which indicates an improvement over BASE. It does look like close to the root cause of improved will-it-scale throughput. Thanks, Fengguang ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [sched,rcu] b84c4e08143: +3.1% will-it-scale.per_thread_ops 2014-04-19 8:11 ` Fengguang Wu @ 2014-04-22 1:50 ` Paul E. McKenney 0 siblings, 0 replies; 4+ messages in thread From: Paul E. McKenney @ 2014-04-22 1:50 UTC (permalink / raw) To: Fengguang Wu; +Cc: LKML, lkp On Sat, Apr 19, 2014 at 04:11:46PM +0800, Fengguang Wu wrote: > On Thu, Apr 17, 2014 at 06:55:03AM -0700, Paul E. McKenney wrote: > > On Thu, Apr 17, 2014 at 12:03:53PM +0800, Fengguang Wu wrote: > > > Hi Paul, > > > > > > FYI, this improves will-it-scale/open1 throughput. > > > > Cool! Not a planned benefit, but I will take it. ;-) > > > > > 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") > > > > But how should I read the data below? I see lots of positive percentages > > and lots of negative percentages for the delta, and all near zero for > > standard deviation. Is the overall improvement an average of these or > > some such? What is being measured? > > There are a lot of things being measured, which are shown after each > "TOTAL". For example, to get an overview of the report: OK, let me see if I understand this... > grep "TOTAL" this_email > > 563496 ~ 0% +3.1% 581059 ~ 0% TOTAL will-it-scale.per_thread_ops > 756894 ~ 0% +2.8% 778452 ~ 0% TOTAL will-it-scale.per_process_ops These two look like improvements, albeit small ones. > 0.57 ~ 0% -2.7% 0.55 ~ 0% TOTAL will-it-scale.scalability This one looks like a degradation, again small. > 346764 ~ 2% -74.0% 90164 ~ 1% TOTAL slabinfo.kmalloc-256.active_objs > 10837 ~ 2% -73.9% 2824 ~ 1% TOTAL slabinfo.kmalloc-256.active_slabs > 10837 ~ 2% -73.9% 2824 ~ 1% TOTAL slabinfo.kmalloc-256.num_slabs > 346821 ~ 2% -73.9% 90393 ~ 1% TOTAL slabinfo.kmalloc-256.num_objs > 105961 ~ 1% -63.0% 39153 ~ 1% TOTAL meminfo.SUnreclaim > 26432 ~ 1% -62.9% 9814 ~ 1% TOTAL proc-vmstat.nr_slab_unreclaimable The above all look great -- about the same amount of work done with a lot less work on the part of the Linux kernel's memory-management system. > 87318 ~ 0% +130.0% 200809 ~ 0% TOTAL softirqs.RCU This one is not so good, as RCU is consuming more time an energy for roughly the same amount of work. > 140354 ~ 1% -47.6% 73490 ~ 0% TOTAL meminfo.Slab > 77391 ~ 1% -46.7% 41235 ~ 2% TOTAL cpuidle.C6-NHM.usage > 38368 ~ 2% -37.6% 23954 ~ 2% TOTAL softirqs.SCHED > 1.24 ~ 4% -35.4% 0.80 ~ 3% TOTAL perf-profile.cpu-cycles.do_notify_resume.int_signal.close These look like improvements, again less work for a given level of throughput. > 1.43 ~ 4% +41.9% 2.03 ~ 4% TOTAL perf-profile.cpu-cycles.rcu_process_callbacks.__do_softirq.irq_exit.smp_apic_timer_in This is another aspect of RCU working harder. One good thing is that there is less work per invocation. This could be consistent with shorter RCU grace-period latencies, which would generally be a good thing. (And yes, I still owe you RCU grace-period-latency measurements!) > rupt.apic_timer_interrupt > 1.27 ~ 3% -30.0% 0.89 ~ 6% TOTAL perf-profile.cpu-cycles.setup_object.isra.46.new_slab.__slab_alloc.kmem_cache_alloc.g Less memory-allocation work, goodness. > empty_filp > 1.54 ~ 7% +35.6% 2.09 ~ 8% TOTAL perf-profile.cpu-cycles.kmem_cache_alloc.getname_flags.getname.do_sys_open.sys_open But more of whatever this turns out to be. More allocations from within the open() system call? > 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 > 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 > en > 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 Mixed results on other aspects of the open() system call? > 0.67 ~16% +33.6% 0.90 ~10% TOTAL perf-profile.cpu-cycles.restore_sigcontext.sys_rt_sigreturn.stub_rt_sigreturn.raise I confess to being lost on this one. > 3.19 ~ 1% +17.4% 3.74 ~ 5% TOTAL perf-profile.cpu-cycles.file_free_rcu.rcu_process_callbacks.__do_softirq.irq_exit.smp More RCU softirqs means more softirq exit overhead, presumably. > ic_timer_interrupt ??? > 4329 ~ 7% +15.2% 4986 ~ 5% TOTAL slabinfo.vm_area_struct.active_objs But increased number of active objects would seem to hint at longer RCU grace-period latencies, in contradiction with the previous hints in the other direction. > 2536 ~ 1% -75.8% 614 ~ 9% TOTAL time.involuntary_context_switches > 32593 ~ 1% -62.1% 12349 ~ 2% TOTAL interrupts.0:IO-APIC-edge.timer These look like improvements. > 6934 ~ 9% +86.2% 12908 ~ 7% TOTAL interrupts.RES Looks like a degradation. Caused by the increase in RCU softirqs? > 490 ~ 1% -37.3% 307 ~ 1% TOTAL vmstat.system.cs > 1639 ~ 0% -8.8% 1495 ~ 0% TOTAL vmstat.system.in > 819681 ~ 0% -3.7% 789527 ~ 0% TOTAL interrupts.LOC These all look like improvements. > > > 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 > > > > So the good case increases involuntary context switches, but helps something > > else? Or does the benefit stem from increased involuntary context switches > > and thus less time spinning or some such? > > In bisect POV, branch BASE is good and HEAD is bad. Which has nothing > to do with the improvement/regression in performance POV. > > Here the HEAD(bisect bad) commit has less involuntary_context_switches > which indicates an improvement over BASE. It does look like close to > the root cause of improved will-it-scale throughput. Ah, that explains it! Would it make sense to add "(HEAD)" to the legend for "[O]"? Thanx, Paul ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-04-22 1:50 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-04-17 4:03 [sched,rcu] b84c4e08143: +3.1% will-it-scale.per_thread_ops Fengguang Wu 2014-04-17 13:55 ` Paul E. McKenney 2014-04-19 8:11 ` Fengguang Wu 2014-04-22 1:50 ` Paul E. McKenney
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