From: Juan Martinez Date: Fri, 16 Jan 2026 21:45:39 +0000 (-0600) Subject: cpufreq/amd-pstate: Add comment explaining nominal_perf usage for performance policy X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=94dbce6c13cd7634f9bdb402248991c95a8c3d57;p=thirdparty%2Flinux.git 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 Signed-off-by: Viresh Kumar --- diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index c45bc98721d24..ec9f38b219de1 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 {