6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>
[ 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@xxxxxxx>
Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Link: https://lore.kernel.org/r/20241021101836.9047-2-gautham.shenoy@xxxxxxx
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 5138aa42caf22..91d3c3b1c2d3b 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1513,7 +1513,7 @@ static int 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);
--
2.43.0
