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

[Jacob Shin <jacob.shin@amd.com>]

On Wed, Mar 27, 2013 at 09:28:56PM +0530, 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.
> 
> V3->V4:
> - We have two instances of all show/store routines for ondemand/conservative
>   governor. One for per-policy instance of governor and other for one governor
>   instance for all policies.
> - Dropped: db9baec cpufreq: Get rid of "struct global_attr".
> - Fixed cpufreq_governor_dbs for multiple policies using same governor instance.
> - Implemented few macro's in cpufreq_governor.h to make above stuff clean.
> - Renamed have_multiple_policies to have_governor_per_policy
> - Some more minor cleanups
> 
> Viresh Kumar (2):
>   cpufreq: Add per policy governor-init/exit infrastructure
>   cpufreq: governor: Implement per policy instances of governors
> 
>  drivers/cpufreq/cpufreq.c              |  36 ++++-
>  drivers/cpufreq/cpufreq_conservative.c | 193 ++++++++++++++----------
>  drivers/cpufreq/cpufreq_governor.c     | 212 +++++++++++++++++---------
>  drivers/cpufreq/cpufreq_governor.h     | 117 +++++++++++++--
>  drivers/cpufreq/cpufreq_ondemand.c     | 263 ++++++++++++++++++++-------------
>  include/linux/cpufreq.h                |  17 ++-
>  6 files changed, 562 insertions(+), 276 deletions(-)
> 
> -- 
> 1.7.12.rc2.18.g61b472e
> 
> 

V4 tested good on AMD machine that the regression was reported on.

Thanks,

Tested-by: Jacob Shin <jacob.shin@amd.com>