Hi Paul, we noticed the below changes on git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git torture.2014.04.18a commit 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 ("sched,rcu: Make cond_resched() report RCU quiescent states")

Comparison 1 - parent commit of 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 vs 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 e119454e74a852f 9234566d3a36c0aead8852e3c --------------- ------------------------- 1035948 ~ 0% +1.6% 1052990 ~ 0% TOTAL will-it-scale.per_thread_ops 1271322 ~ 0% +1.8% 1294004 ~ 0% TOTAL will-it-scale.per_process_ops 0.63 ~ 0% -5.2% 0.60 ~ 0% TOTAL will-it-scale.scalability 22470 ~ 2% +1302.6% 315168 ~ 2% TOTAL time.involuntary_context_switches 84265 ~ 5% +1047.1% 966581 ~ 1% TOTAL interrupts.IWI 1828 ~44% +189.6% 5295 ~13% TOTAL time.voluntary_context_switches 5337 ~ 1% +82.1% 9720 ~ 1% TOTAL vmstat.system.cs 118599 ~ 0% -30.4% 82545 ~ 0% TOTAL interrupts.0:IO-APIC-edge.timer 224021 ~ 4% +34.7% 301858 ~ 2% TOTAL interrupts.RES 25148 ~ 0% +7.0% 26917 ~ 0% TOTAL vmstat.system.in 7063439 ~ 0% -5.2% 6694536 ~ 0% TOTAL interrupts.LOC 188866 ~ 0% -3.1% 183008 ~ 0% TOTAL interrupts.NMI 188866 ~ 0% -3.1% 183008 ~ 0% TOTAL interrupts.PMI 3720 ~ 0% -1.5% 3665 ~ 0% TOTAL time.system_time 1215 ~ 0% -1.4% 1198 ~ 0% TOTAL time.percent_of_cpu_this_job_got Comparison 2 - b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 vs 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 Fengguang has reported stats changes about b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 to you days ago. 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") Let's have a compare here. b84c4e08143c98d 9234566d3a36c0aead8852e3c --------------- ------------------------- 809309 ~ 0% -2.6% 788400 ~ 0% TOTAL will-it-scale.per_process_ops 0.61 ~ 0% -1.9% 0.60 ~ 0% TOTAL will-it-scale.scalability 434080 ~ 0% -1.5% 427643 ~ 0% TOTAL will-it-scale.per_thread_ops 4 ~11% +1.2e+05% 5249 ~ 2% TOTAL interrupts.IWI 607 ~ 7% +28.0% 778 ~14% TOTAL interrupts.47:PCI-MSI-edge.eth0 12349 ~ 2% -14.6% 10548 ~ 1% TOTAL interrupts.0:IO-APIC-edge.timer 3078 ~ 3% +20.9% 3722 ~ 6% TOTAL interrupts.RES Comparison 3 - parent commit of b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 vs b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 Duplicated with Fengguang's report. Help you to see these info in a page :) ad86a04266f9b49 b84c4e08143c98dad4b4d139f --------------- ------------------------- 676264 ~ 0% +3.3% 698461 ~ 0% TOTAL will-it-scale.per_thread_ops 1174547 ~ 0% +3.0% 1209307 ~ 0% TOTAL will-it-scale.per_process_ops 1.67 ~ 0% -2.3% 1.63 ~ 0% TOTAL will-it-scale.scalability 10522 ~ 2% +921.2% 107463 ~ 1% TOTAL time.involuntary_context_switches 77671 ~ 3% +67.0% 129688 ~ 3% TOTAL interrupts.RES 99502 ~ 0% -27.8% 71813 ~ 0% TOTAL interrupts.0:IO-APIC-edge.timer 2554 ~ 0% +49.1% 3809 ~ 1% TOTAL vmstat.system.cs 11524 ~ 0% -2.3% 11259 ~ 0% TOTAL vmstat.system.in 213 ~ 0% -4.3% 204 ~ 0% TOTAL time.system_time 74 ~ 0% -4.1% 71 ~ 0% TOTAL time.percent_of_cpu_this_job_got 3495099 ~ 0% -3.1% 3387173 ~ 0% TOTAL interrupts.LOC Thanks, Jet

./runtest.py open2 32 1 4 6 8

On 04/22/2014 09:59 AM, Paul E. McKenney wrote: >On Mon, Apr 21, 2014 at 02:28:21PM +0800, Jet Chen wrote: >>Hi Paul, >> >>we noticed the below changes on >>git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git torture.2014.04.18a >>commit 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 ("sched,rcu: Make cond_resched() report RCU quiescent states") > >My impression of these statistics is that this commit results in huge >numbers of additional context switches and interrupts, but has a slightly >positive effect on performance and a larger negative effect on >scalability. > >Is this a reasonable interpretation? > Yes, you're right.

>>Comparison 1 - parent commit of 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 vs 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 >> >>e119454e74a852f 9234566d3a36c0aead8852e3c >>--------------- ------------------------- >> 1035948 ~ 0% +1.6% 1052990 ~ 0% TOTAL will-it-scale.per_thread_ops >> 1271322 ~ 0% +1.8% 1294004 ~ 0% TOTAL will-it-scale.per_process_ops >> 0.63 ~ 0% -5.2% 0.60 ~ 0% TOTAL will-it-scale.scalability >> 22470 ~ 2% +1302.6% 315168 ~ 2% TOTAL time.involuntary_context_switches >> 84265 ~ 5% +1047.1% 966581 ~ 1% TOTAL interrupts.IWI >> 1828 ~44% +189.6% 5295 ~13% TOTAL time.voluntary_context_switches >> 5337 ~ 1% +82.1% 9720 ~ 1% TOTAL vmstat.system.cs >> 118599 ~ 0% -30.4% 82545 ~ 0% TOTAL interrupts.0:IO-APIC-edge.timer >> 224021 ~ 4% +34.7% 301858 ~ 2% TOTAL interrupts.RES >> 25148 ~ 0% +7.0% 26917 ~ 0% TOTAL vmstat.system.in >> 7063439 ~ 0% -5.2% 6694536 ~ 0% TOTAL interrupts.LOC >> 188866 ~ 0% -3.1% 183008 ~ 0% TOTAL interrupts.NMI >> 188866 ~ 0% -3.1% 183008 ~ 0% TOTAL interrupts.PMI >> 3720 ~ 0% -1.5% 3665 ~ 0% TOTAL time.system_time >> 1215 ~ 0% -1.4% 1198 ~ 0% TOTAL time.percent_of_cpu_this_job_got >> >> >>Comparison 2 - b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 vs 9234566d3a36c0aead8852e3c2ca94cd8ebfe219 >> >>Fengguang has reported stats changes about b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 to you days ago. >>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") >> >>Let's have a compare here. >> >>b84c4e08143c98d 9234566d3a36c0aead8852e3c >>--------------- ------------------------- >> 809309 ~ 0% -2.6% 788400 ~ 0% TOTAL will-it-scale.per_process_ops >> 0.61 ~ 0% -1.9% 0.60 ~ 0% TOTAL will-it-scale.scalability >> 434080 ~ 0% -1.5% 427643 ~ 0% TOTAL will-it-scale.per_thread_ops >> 4 ~11% +1.2e+05% 5249 ~ 2% TOTAL interrupts.IWI >> 607 ~ 7% +28.0% 778 ~14% TOTAL interrupts.47:PCI-MSI-edge.eth0 >> 12349 ~ 2% -14.6% 10548 ~ 1% TOTAL interrupts.0:IO-APIC-edge.timer >> 3078 ~ 3% +20.9% 3722 ~ 6% TOTAL interrupts.RES >> >> >>Comparison 3 - parent commit of b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 vs b84c4e08143c98dad4b4d139f08db0b98b0d3ec4 >> >>Duplicated with Fengguang's report. Help you to see these info in a page :) >> >>ad86a04266f9b49 b84c4e08143c98dad4b4d139f >>--------------- ------------------------- >> 676264 ~ 0% +3.3% 698461 ~ 0% TOTAL will-it-scale.per_thread_ops >> 1174547 ~ 0% +3.0% 1209307 ~ 0% TOTAL will-it-scale.per_process_ops >> 1.67 ~ 0% -2.3% 1.63 ~ 0% TOTAL will-it-scale.scalability >> 10522 ~ 2% +921.2% 107463 ~ 1% TOTAL time.involuntary_context_switches >> 77671 ~ 3% +67.0% 129688 ~ 3% TOTAL interrupts.RES >> 99502 ~ 0% -27.8% 71813 ~ 0% TOTAL interrupts.0:IO-APIC-edge.timer >> 2554 ~ 0% +49.1% 3809 ~ 1% TOTAL vmstat.system.cs >> 11524 ~ 0% -2.3% 11259 ~ 0% TOTAL vmstat.system.in >> 213 ~ 0% -4.3% 204 ~ 0% TOTAL time.system_time >> 74 ~ 0% -4.1% 71 ~ 0% TOTAL time.percent_of_cpu_this_job_got >> 3495099 ~ 0% -3.1% 3387173 ~ 0% TOTAL interrupts.LOC >> >> >> >> >>Thanks, >>Jet >> >> >> > >>./runtest.py open2 32 1 4 6 8 >> >> >