diff options
| author | Juan Martinez <juan.martinez@amd.com> | 2026-01-16 15:45:39 -0600 |
|---|---|---|
| committer | Viresh Kumar <viresh.kumar@linaro.org> | 2026-01-27 11:21:23 +0530 |
| commit | 94dbce6c13cd7634f9bdb402248991c95a8c3d57 (patch) | |
| tree | a46706a5c78e8098dcd384efc5698231858191cc /drivers/cpufreq | |
| parent | 8c376f337a7e31c42949247e24eaad9a30d6c62c (diff) | |
cpufreq/amd-pstate: Add comment explaining nominal_perf usage for performance policy
Add comment explaining why nominal_perf is used for MinPerf when the
CPU frequency policy is set to CPUFREQ_POLICY_PERFORMANCE, rather than
using highest_perf or lowest_nonlinear_perf.
Signed-off-by: Juan Martinez <juan.martinez@amd.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/amd-pstate.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index c45bc98721d2..ec9f38b219de 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -636,6 +636,19 @@ static void amd_pstate_update_min_max_limit(struct cpufreq_policy *policy) WRITE_ONCE(cpudata->max_limit_freq, policy->max); if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) { + /* + * For performance policy, set MinPerf to nominal_perf rather than + * highest_perf or lowest_nonlinear_perf. + * + * Per commit 0c411b39e4f4c, using highest_perf was observed + * to cause frequency throttling on power-limited platforms, leading to + * performance regressions. Using lowest_nonlinear_perf would limit + * performance too much for HPC workloads requiring high frequency + * operation and minimal wakeup latency from idle states. + * + * nominal_perf therefore provides a balance by avoiding throttling + * while still maintaining enough performance for HPC workloads. + */ perf.min_limit_perf = min(perf.nominal_perf, perf.max_limit_perf); WRITE_ONCE(cpudata->min_limit_freq, min(cpudata->nominal_freq, cpudata->max_limit_freq)); } else { |