6.6-stable review patch. If anyone has any objections, please let me know.
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From: Gautham R. Shenoy gautham.shenoy@amd.com
[ Upstream commit 0c411b39e4f4ce8861301fa201cb4f817751311e ]
The amd-pstate driver sets CPPC_REQ.min_perf to CPPC_REQ.max_perf when in active mode with performance governor. Typically CPPC_REQ.max_perf is set to CPPC.highest_perf. This causes frequency throttling on power-limited platforms which causes performance regressions on certain classes of workloads.
Hence, set the CPPC_REQ.min_perf to the CPPC.nominal_perf or CPPC_REQ.max_perf, whichever is lower of the two.
Fixes: ffa5096a7c33 ("cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors") Signed-off-by: Gautham R. Shenoy gautham.shenoy@amd.com Reviewed-by: Mario Limonciello mario.limonciello@amd.com Link: https://lore.kernel.org/r/20241021101836.9047-2-gautham.shenoy@amd.com Signed-off-by: Mario Limonciello mario.limonciello@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/amd-pstate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 8c16d67b98bfe..cdead37d0823a 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -1383,7 +1383,7 @@ static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy) value = READ_ONCE(cpudata->cppc_req_cached);
if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) - min_perf = max_perf; + min_perf = min(cpudata->nominal_perf, max_perf);
/* Initial min/max values for CPPC Performance Controls Register */ value &= ~AMD_CPPC_MIN_PERF(~0L);