[AMD Official Use Only - General] Hi Lucas: > -----Original Message----- > From: Lucas Lee Jing Yi <lucasleeeeeeeee@xxxxxxxxx> > Sent: Monday, February 19, 2024 12:11 AM > To: rafael@xxxxxxxxxx > Cc: Yuan, Perry <Perry.Yuan@xxxxxxx>; Du, Xiaojian > <Xiaojian.Du@xxxxxxx>; Deucher, Alexander > <Alexander.Deucher@xxxxxxx>; bp@xxxxxxxxx; Sharma, Deepak > <Deepak.Sharma@xxxxxxx>; Meng, Li (Jassmine) <Li.Meng@xxxxxxx>; > linux-acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux- > kselftest@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx; Limonciello, Mario > <Mario.Limonciello@xxxxxxx>; Fontenot, Nathan > <Nathan.Fontenot@xxxxxxx>; oleksandr@xxxxxxxxxxxxxx; > rafael.j.wysocki@xxxxxxxxx; Huang, Ray <Ray.Huang@xxxxxxx>; Huang, > Shimmer <Shimmer.Huang@xxxxxxx>; skhan@xxxxxxxxxxxxxxxxxxx; > viresh.kumar@xxxxxxxxxx; x86@xxxxxxxxxx; Lucas Lee Jing Yi > <lucasleeeeeeeee@xxxxxxxxx> > 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@xxxxxxxxx> > --- > 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@xxxxxxx>
