Re: [PATCH V4 0/2] Implement per policy instance of governor

From: Rafael J. Wysocki
Date: Fri Mar 29 2013 - 22:09:43 EST


On Wednesday, March 27, 2013 09:28:56 PM Viresh Kumar wrote:
> Hi Guys,
>
> All patches are pushed here for others to apply (you can apply from mail to):
> http://git.linaro.org/gitweb?p=people/vireshk/linux.git;a=shortlog;h=refs/heads/governor-per-policy-v4
>
> Currently, there can't be multiple instances of single governor_type. If we have
> a multi-package system, where we have multiple instances of struct policy (per
> package), we can't have multiple instances of same governor. i.e. We can't have
> multiple instances of ondemand governor for multiple packages.
>
> Governors directory in sysfs is created at /sys/devices/system/cpu/cpufreq/
> governor-name/. Which again reflects that there can be only one instance of a
> governor_type in the system.
>
> This is a bottleneck for multicluster system, where we want different packages
> to use same governor type, but with different tunables.
>
> This patchset is inclined towards fixing this issue. Now we will create
> governors directory in cpu/cpu*/cpufreq/<gov> for platforms which have multiple
> struct policy alive at any moment. Platform drivers requiring this feature must
> set have_governor_per_policy variable in their instance of cpufreq_driver. For
> others the interface is kept same: cpu/cpufreq/<gov>.
>
>
> This is V4 of this patchset. V3 is already applied by Rafael in his linux-next
> branch. Jacob Shin reported some regressions with this patchset and when I went
> into testing it with his configuration I found more issues then what he
> reported.
>
> To test these over linux-next you need to revert following first:
> db9baec cpufreq: Get rid of "struct global_attr"
> 86bd6f0 cpufreq: governor: Implement per policy instances of governors
> 8ae67b1 cpufreq: Add per policy governor-init/exit infrastructure
>
> I have tested this for following now and believe there are no more regressions
> with it:
> - platform with a single policy instance or single group of cpu
> - platform with multiple policies but which don't want per policy instance of
> governor
> - platform with multiple policies and which want per policy instance of governor
>
> I have tried with different settings and combinations of governors.
>
> @Rafael: To simplify your life I have sorted out your branch and you can simply
> pickup the complete branch that I have pushed.

I've applied these two patches and re-applied the queue on top of them.

All is in my linux-next branch now.

Thanks,
Rafael


--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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