RE: [PATCH 7/8] cpufreq: amd-pstate: Optimize amd_pstate_update_limits()

Yuan, Perry
2024-08-27T06:48:59Z

[AMD Official Use Only - AMD Internal Distribution Only]

> -----Original Message-----
> From: Mario Limonciello <superm1@kernel.org>
> Sent: Tuesday, August 27, 2024 5:14 AM
> To: Borislav Petkov <bp@alien8.de>; Shenoy, Gautham Ranjal
> <gautham.shenoy@amd.com>; Yuan, Perry <Perry.Yuan@amd.com>
> Cc: maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT) <x86@kernel.org>;
> Rafael J . Wysocki <rafael@kernel.org>; open list:X86 ARCHITECTURE (32-BIT
> AND 64-BIT) <linux-kernel@vger.kernel.org>; open list:ACPI <linux-
> acpi@vger.kernel.org>; open list:CPU FREQUENCY SCALING FRAMEWORK
> <linux-pm@vger.kernel.org>; Limonciello, Mario
> <Mario.Limonciello@amd.com>
> Subject: [PATCH 7/8] cpufreq: amd-pstate: Optimize
> amd_pstate_update_limits()
>
> From: Mario Limonciello <mario.limonciello@amd.com>
>
> Don't take and release the mutex when prefcore isn't present and avoid
> initialization of variables that will be initially set in the function.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> drivers/cpufreq/amd-pstate.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 75568d0f84623..ed05d7a0add10 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -798,17 +798,17 @@ static void amd_pstate_update_limits(unsigned int
> cpu)
> int ret;
> bool highest_perf_changed = false;
>
> - mutex_lock(&amd_pstate_driver_lock);
> - if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore))
> - goto free_cpufreq_put;
> + if (!amd_pstate_prefcore)
> + return;
>
> + mutex_lock(&amd_pstate_driver_lock);
> ret = amd_get_highest_perf(cpu, &cur_high);
> if (ret)
> goto free_cpufreq_put;
>
> prev_high = READ_ONCE(cpudata->prefcore_ranking);
> - if (prev_high != cur_high) {
> - highest_perf_changed = true;
> + highest_perf_changed = (prev_high != cur_high);
> + if (highest_perf_changed) {
> WRITE_ONCE(cpudata->prefcore_ranking, cur_high);
>
> if (cur_high < CPPC_MAX_PERF)
> --
> 2.43.0
>

Reviewed-by: Perry Yuan <perry.yuan@amd.com>

Best Regards.

Perry.