Re: [PATCH v2 2/7] cpufreq: set invariance scale factor on transition end

Viresh Kumar
2020-07-30T04:15:16Z

On 22-07-20, 10:37, Ionela Voinescu wrote:
> While the move of the invariance setter calls (arch_set_freq_scale())
> from cpufreq drivers to cpufreq core maintained the previous
> functionality for existing drivers that use target_index() and
> fast_switch() for frequency switching, it also gives the possibility
> of adding support for users of the target() callback, which is exploited
> here.
>
> To be noted that the target() callback has been flagged as deprecated
> since:
>
> commit 9c0ebcf78fde ("cpufreq: Implement light weight ->target_index() routine")
>
> It also doesn't have that many users:
>
> cpufreq-nforce2.c:371:2: .target = nforce2_target,
> cppc_cpufreq.c:416:2: .target = cppc_cpufreq_set_target,
> gx-suspmod.c:439:2: .target = cpufreq_gx_target,
> pcc-cpufreq.c:573:2: .target = pcc_cpufreq_target,
>
> Similarly to the path taken for target_index() calls in the cpufreq core
> during a frequency change, all of the drivers above will mark the end of a
> frequency change by a call to cpufreq_freq_transition_end().
>
> Therefore, cpufreq_freq_transition_end() can be used as the location for
> the arch_set_freq_scale() call to potentially inform the scheduler of the
> frequency change.
>
> This change maintains the previous functionality for the drivers that
> implement the target_index() callback, while also adding support for the
> few drivers that implement the deprecated target() callback.
>
> Two notes are worthwhile here:
> - In __target_index(), cpufreq_freq_transition_end() is called only for
> drivers that have synchronous notifications enabled. There is only one
> driver that disables them,
>
> drivers/cpufreq/powernow-k8.c:1142: .flags = CPUFREQ_ASYNC_NOTIFICATION,
>
> which is deprecated.

I don't think this is deprecated.

--
viresh