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?
Thanx, Paul
> 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
>
>
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