| Message ID | 20240218161435.38312-2-lucasleeeeeeeee@gmail.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | amd_pstate: fix erroneous highest_perf value on some CPUs | expand |
[AMD Official Use Only - General] Hi Lucas: > -----Original Message----- > From: Lucas Lee Jing Yi <lucasleeeeeeeee@gmail.com> > Sent: Monday, February 19, 2024 12:11 AM > To: rafael@kernel.org > Cc: Yuan, Perry <Perry.Yuan@amd.com>; Du, Xiaojian > <Xiaojian.Du@amd.com>; Deucher, Alexander > <Alexander.Deucher@amd.com>; bp@alien8.de; Sharma, Deepak > <Deepak.Sharma@amd.com>; Meng, Li (Jassmine) <Li.Meng@amd.com>; > linux-acpi@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > kselftest@vger.kernel.org; linux-pm@vger.kernel.org; Limonciello, Mario > <Mario.Limonciello@amd.com>; Fontenot, Nathan > <Nathan.Fontenot@amd.com>; oleksandr@natalenko.name; > rafael.j.wysocki@intel.com; Huang, Ray <Ray.Huang@amd.com>; Huang, > Shimmer <Shimmer.Huang@amd.com>; skhan@linuxfoundation.org; > viresh.kumar@linaro.org; x86@kernel.org; Lucas Lee Jing Yi > <lucasleeeeeeeee@gmail.com> > Subject: [PATCH] [PATCH] amd_pstate: fix erroneous highest_perf value on > some CPUs > > Caution: This message originated from an External Source. Use proper > caution when opening attachments, clicking links, or responding. > > > On a Ryzen 7840HS the highest_perf value is 196, not 166 as AMD assumed. > This leads to the advertised max clock speed to only be 4.35ghz instead of > 5.14ghz , leading to a large degradation in performance. > > Fix the broken assumption and revert back to the old logic for getting > highest_perf. > > TEST: > Geekbench 6 Before Patch: > Single Core: 2325 (-22%)! > Multi Core: 11335 (-10%) > > Geekbench 6 AFTER Patch: > Single Core: 2635 > Multi Core: 12487 > > Signed-off-by: Lucas Lee Jing Yi <lucasleeeeeeeee@gmail.com> > --- > drivers/cpufreq/amd-pstate.c | 22 ++++++++++------------ > 1 file changed, 10 insertions(+), 12 deletions(-) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index 08e112444c27..54df68773620 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -50,7 +50,6 @@ > > #define AMD_PSTATE_TRANSITION_LATENCY 20000 > #define AMD_PSTATE_TRANSITION_DELAY 1000 > -#define AMD_PSTATE_PREFCORE_THRESHOLD 166 > > /* > * TODO: We need more time to fine tune processors with shared memory > solution @@ -299,15 +298,12 @@ static int pstate_init_perf(struct > amd_cpudata *cpudata) > &cap1); > if (ret) > return ret; > - > - /* For platforms that do not support the preferred core feature, the > - * highest_pef may be configured with 166 or 255, to avoid max > frequency > - * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) > value as > - * the default max perf. > + > + /* Some CPUs have different highest_perf from others, it is safer > + * to read it than to assume some erroneous value, leading to > performance issues. > */ > - if (cpudata->hw_prefcore) > - highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD; > - else > + highest_perf = amd_get_highest_perf(); > + if(highest_perf > AMD_CPPC_HIGHEST_PERF(cap1)) > highest_perf = AMD_CPPC_HIGHEST_PERF(cap1); > > WRITE_ONCE(cpudata->highest_perf, highest_perf); @@ -329,9 +325,11 > @@ static int cppc_init_perf(struct amd_cpudata *cpudata) > if (ret) > return ret; > > - if (cpudata->hw_prefcore) > - highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD; > - else > + /* Some CPUs have different highest_perf from others, it is safer > + * to read it than to assume some erroneous value, leading to > performance issues. > + */ > + highest_perf = amd_get_highest_perf(); > + if(highest_perf > cppc_perf.highest_perf) > highest_perf = cppc_perf.highest_perf; > > WRITE_ONCE(cpudata->highest_perf, highest_perf); > -- > 2.43.2 [Meng, Li (Jassmine)] Reviewed-by: Li Meng < li.meng@amd.com>
Hello. On neděle 18. února 2024 17:10:31 CET Lucas Lee Jing Yi wrote: > On a Ryzen 7840HS the highest_perf value is 196, not 166 as AMD assumed. > This leads to the advertised max clock speed to only be 4.35ghz instead of 5.14ghz , leading to a large degradation in performance. > > Fix the broken assumption and revert back to the old logic for getting highest_perf. > > TEST: > Geekbench 6 Before Patch: > Single Core: 2325 (-22%)! > Multi Core: 11335 (-10%) > > Geekbench 6 AFTER Patch: > Single Core: 2635 > Multi Core: 12487 > > Signed-off-by: Lucas Lee Jing Yi <lucasleeeeeeeee@gmail.com> > --- > drivers/cpufreq/amd-pstate.c | 22 ++++++++++------------ > 1 file changed, 10 insertions(+), 12 deletions(-) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index 08e112444c27..54df68773620 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -50,7 +50,6 @@ > > #define AMD_PSTATE_TRANSITION_LATENCY 20000 > #define AMD_PSTATE_TRANSITION_DELAY 1000 > -#define AMD_PSTATE_PREFCORE_THRESHOLD 166 > > /* > * TODO: We need more time to fine tune processors with shared memory solution > @@ -299,15 +298,12 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) > &cap1); > if (ret) > return ret; > - > - /* For platforms that do not support the preferred core feature, the > - * highest_pef may be configured with 166 or 255, to avoid max frequency > - * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as > - * the default max perf. > + > + /* Some CPUs have different highest_perf from others, it is safer > + * to read it than to assume some erroneous value, leading to performance issues. > */ > - if (cpudata->hw_prefcore) > - highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD; > - else > + highest_perf = amd_get_highest_perf(); > + if(highest_perf > AMD_CPPC_HIGHEST_PERF(cap1)) > highest_perf = AMD_CPPC_HIGHEST_PERF(cap1); > > WRITE_ONCE(cpudata->highest_perf, highest_perf); > @@ -329,9 +325,11 @@ static int cppc_init_perf(struct amd_cpudata *cpudata) > if (ret) > return ret; > > - if (cpudata->hw_prefcore) > - highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD; > - else > + /* Some CPUs have different highest_perf from others, it is safer > + * to read it than to assume some erroneous value, leading to performance issues. > + */ > + highest_perf = amd_get_highest_perf(); > + if(highest_perf > cppc_perf.highest_perf) > highest_perf = cppc_perf.highest_perf; > > WRITE_ONCE(cpudata->highest_perf, highest_perf); > Please pay attention to trailing whitespaces, adding whitespaces to blank lines, and whitespaces between `if` and opening `(`. `scripts/checkpatch.pl` may help you with that. Thank you.
Hi Oleksandr, Thanks, sent in a new patch with the recommendations highlighted by the script. Regards, Lucas
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 08e112444c27..54df68773620 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -50,7 +50,6 @@ #define AMD_PSTATE_TRANSITION_LATENCY 20000 #define AMD_PSTATE_TRANSITION_DELAY 1000 -#define AMD_PSTATE_PREFCORE_THRESHOLD 166 /* * TODO: We need more time to fine tune processors with shared memory solution @@ -299,15 +298,12 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) &cap1); if (ret) return ret; - - /* For platforms that do not support the preferred core feature, the - * highest_pef may be configured with 166 or 255, to avoid max frequency - * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as - * the default max perf. + + /* Some CPUs have different highest_perf from others, it is safer + * to read it than to assume some erroneous value, leading to performance issues. */ - if (cpudata->hw_prefcore) - highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD; - else + highest_perf = amd_get_highest_perf(); + if(highest_perf > AMD_CPPC_HIGHEST_PERF(cap1)) highest_perf = AMD_CPPC_HIGHEST_PERF(cap1); WRITE_ONCE(cpudata->highest_perf, highest_perf); @@ -329,9 +325,11 @@ static int cppc_init_perf(struct amd_cpudata *cpudata) if (ret) return ret; - if (cpudata->hw_prefcore) - highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD; - else + /* Some CPUs have different highest_perf from others, it is safer + * to read it than to assume some erroneous value, leading to performance issues. + */ + highest_perf = amd_get_highest_perf(); + if(highest_perf > cppc_perf.highest_perf) highest_perf = cppc_perf.highest_perf; WRITE_ONCE(cpudata->highest_perf, highest_perf);
On a Ryzen 7840HS the highest_perf value is 196, not 166 as AMD assumed. This leads to the advertised max clock speed to only be 4.35ghz instead of 5.14ghz , leading to a large degradation in performance. Fix the broken assumption and revert back to the old logic for getting highest_perf. TEST: Geekbench 6 Before Patch: Single Core: 2325 (-22%)! Multi Core: 11335 (-10%) Geekbench 6 AFTER Patch: Single Core: 2635 Multi Core: 12487 Signed-off-by: Lucas Lee Jing Yi <lucasleeeeeeeee@gmail.com> --- drivers/cpufreq/amd-pstate.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-)