Messages in this thread | | | Date | Tue, 11 Oct 2016 08:28:47 +0200 | From | Andreas Herrmann <> | Subject | Re: [PATCH 1/1] cpufreq: pcc-cpufreq: Re-introduce deadband effect to reduce number of frequency changes |
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On Wed, Oct 05, 2016 at 10:47:53AM +0530, Viresh Kumar wrote: > Sorry for being late Andreas :( > > On 14-09-16, 16:56, Andreas Herrmann wrote: > > First of all, thanks for your hardwork in getting these numbers out. > Really appreciate it. > > > Below is some trace data. I hope it is of some help. > > > > (A) - sampling 10s period when system is idle > > (B) - sampling 10s period when system partially loaded (kernel > > compilation using 2 jobs) > > > > (1) 4.8-rc5 > > (2) 4.8-rc5 with my patch (reintro of deadband effect within > > pcc-cpufreq) > > (3) 4.8-rc5 with reversal of 6393d6a102 (cpufreq: ondemand: Eliminate > > the deadband effect) > > > > Let me know whether you are looking for other trace data wrt this > > issue. > > > > > > Thanks, > > > > Andreas > > > > --- > > > > (A)-(1) > > > > # Total Lost Samples: 0 > > # Samples: 41 of event 'power:cpu_frequency' > > # Event count (approx.): 41 > > # Overhead Command Shared Object Symbol > > # ........ ............ ................ ............................. > > 39.02% kworker/14:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 29.27% kworker/0:0 [kernel.vmlinux] [k] cpufreq_notify_transition > > 19.51% kworker/10:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 7.32% kworker/5:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 2.44% kworker/23:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 2.44% kworker/40:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > > > (A)-(2) > > > > # Total Lost Samples: 0 > > # Samples: 6 of event 'power:cpu_frequency' > > # Event count (approx.): 6 > > # Overhead Command Shared Object Symbol > > # ........ ............ ................ ............................. > > 33.33% kworker/1:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 16.67% kworker/16:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 16.67% kworker/22:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 16.67% kworker/26:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 16.67% kworker/33:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > > > (A)-(3) > > > > # Total Lost Samples: 0 > > # Samples: 7 of event 'power:cpu_frequency' > > # Event count (approx.): 7 > > # Overhead Command Shared Object Symbol > > # ........ ............ ................ ............................. > > 28.57% kworker/58:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 14.29% kworker/19:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 14.29% kworker/20:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 14.29% kworker/22:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 14.29% kworker/23:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 14.29% kworker/35:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > > > --- > > > > (B)-(1) > > > > # Total Lost Samples: 0 > > # Samples: 2K of event 'power:cpu_frequency' > > # Event count (approx.): 2382 > > # Overhead Command Shared Object Symbol > > # ........ ............ ................ ............................. > > 5.75% kworker/0:0 [kernel.vmlinux] [k] cpufreq_notify_transition > > 4.16% kworker/12:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 3.11% kworker/17:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 2.94% kworker/2:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 2.73% kworker/19:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > ... > > > > (B)-(2) > > > > # Total Lost Samples: 0 > > # Samples: 320 of event 'power:cpu_frequency' > > # Event count (approx.): 320 > > # Overhead Command Shared Object Symbol > > # ........ ............ ................ ............................. > > 4.69% kworker/56:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 4.06% kworker/12:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 4.06% kworker/28:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 4.06% kworker/6:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > 3.75% kworker/32:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > ... > > > > (B)-(3) > > > > # Total Lost Samples: 0 > > # Samples: 333 of event 'power:cpu_frequency' > > # Event count (approx.): 333 > > # Overhead Command Shared Object Symbol > > # ........ ............ ................ ............................. > > 4.80% kworker/51:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 4.50% kworker/39:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 4.20% kworker/47:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 3.90% kworker/59:1 [kernel.vmlinux] [k] cpufreq_notify_transition > > 3.90% kworker/7:2 [kernel.vmlinux] [k] cpufreq_notify_transition > > ... > > I am worried by all of these.. So, its not the DVFS transition which > took time, but cpufreq_notify_transition(). And probably one of the > drivers in your setup is screwing up here, which has registered with > cpufreq_register_notifier(). > > Can you please take a look at that ? Just check which all routines are > getting called as part of srcu_notifier_call_chain().
I'll take a look into this.
> Also a simple (hacky) solution to fix the problem you have got is to > divide the range of frequency in steps (which you have already done > AFAICT in one of your patches) and not mention the frequencies that > were part of the deadband earlier. That will keep the CPU at either > low freq or some higher freqs.
Yes, seems worth to try this.
> But I am quite sure that we have an abuser here and we better find it > now.
Thanks,
Andreas
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