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| author | Wyes Karny <wyes.karny@amd.com> | 2022-11-17 15:35:37 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-11-22 19:57:14 +0100 |
| commit | 919f4557696939625085435ebde09a539de2349c (patch) | |
| tree | 02bf191d46ee888ab41ffa7ed2b33c35090f2cae | |
| parent | cdcc5ef26b39c3d02d4e69c0352b007ebe438a22 (diff) | |
| download | linux-919f4557696939625085435ebde09a539de2349c.tar.bz2 | |
cpufreq: amd-pstate: cpufreq: amd-pstate: reset MSR_AMD_PERF_CTL register at init
MSR_AMD_PERF_CTL is guaranteed to be 0 on a cold boot. However, on a
kexec boot, for instance, it may have a non-zero value (if the cpu was
in a non-P0 Pstate). In such cases, the cores with non-P0 Pstates at
boot will never be pushed to P0, let alone boost frequencies.
Kexec is a common workflow for reboot on Linux and this creates a
regression in performance. Fix it by explicitly setting the
MSR_AMD_PERF_CTL to 0 during amd_pstate driver init.
Cc: All applicable <stable@vger.kernel.org>
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | drivers/cpufreq/amd-pstate.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index ace7d50cf2ac..d844c6f97caf 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -424,12 +424,22 @@ static void amd_pstate_boost_init(struct amd_cpudata *cpudata) amd_pstate_driver.boost_enabled = true; } +static void amd_perf_ctl_reset(unsigned int cpu) +{ + wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0); +} + static int amd_pstate_cpu_init(struct cpufreq_policy *policy) { int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret; struct device *dev; struct amd_cpudata *cpudata; + /* + * Resetting PERF_CTL_MSR will put the CPU in P0 frequency, + * which is ideal for initialization process. + */ + amd_perf_ctl_reset(policy->cpu); dev = get_cpu_device(policy->cpu); if (!dev) return -ENODEV; |