| Message ID | 20240118120513.1018808-1-srinivas.pandruvada@linux.intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | cpufreq: intel_pstate: Directly use stored ratios for max frequencies | expand |
On Mon, Jan 22, 2024 at 12:35 PM srinivas pandruvada <srinivas.pandruvada@linux.intel.com> wrote: > > On Mon, 2024-01-22 at 11:53 +0100, Rafael J. Wysocki wrote: > > On Thursday, January 18, 2024 1:05:13 PM CET Srinivas Pandruvada > > wrote: > > > Avoid unnecessary calculation for converting frequency to > > > performance > > > ratio by using a scaling factor for the maximum non turbo and turbo > > > > [...] > > > --- > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Subject: [PATCH v1] cpufreq: intel_pstate: Refine computation of P- > > state for given frequency > > > > On systems using HWP, if a given frequency is equal to the maximum > > turbo > > frequency or the maximum non-turbo frequency, the HWP performance > > level > > corresponding to it is already known and can be used directly without > > any computation. > > > > Accordingly, adjust the code to use the known HWP performance levels > > in > > the cases mentioned above. > > > > This also helps to avoid limiting CPU capacity artificially in some > > cases when the BIOS produces the HWP_CAP numbers using a different > > E-core-to-P-core performance scaling factor than expected by the > > kernel. > > > > Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known > > scaling factor for P-cores") > > Cc: 6.1+ <stable@vger.kernel.org> # 6.1+ > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > --- > > Tested on the system which showed the issue, this patch work fine. So I'm going to add a Tested-by from you to it or please let me know if you don't want me to do so.
On 1/22/24 03:46, Rafael J. Wysocki wrote: > On Mon, Jan 22, 2024 at 12:35 PM srinivas pandruvada > <srinivas.pandruvada@linux.intel.com> wrote: >> On Mon, 2024-01-22 at 11:53 +0100, Rafael J. Wysocki wrote: >>> On Thursday, January 18, 2024 1:05:13 PM CET Srinivas Pandruvada >>> wrote: >>>> Avoid unnecessary calculation for converting frequency to >>>> performance >>>> ratio by using a scaling factor for the maximum non turbo and turbo >> [...] >> >>> --- >>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> >>> Subject: [PATCH v1] cpufreq: intel_pstate: Refine computation of P- >>> state for given frequency >>> >>> On systems using HWP, if a given frequency is equal to the maximum >>> turbo >>> frequency or the maximum non-turbo frequency, the HWP performance >>> level >>> corresponding to it is already known and can be used directly without >>> any computation. >>> >>> Accordingly, adjust the code to use the known HWP performance levels >>> in >>> the cases mentioned above. >>> >>> This also helps to avoid limiting CPU capacity artificially in some >>> cases when the BIOS produces the HWP_CAP numbers using a different >>> E-core-to-P-core performance scaling factor than expected by the >>> kernel. >>> >>> Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known >>> scaling factor for P-cores") >>> Cc: 6.1+ <stable@vger.kernel.org> # 6.1+ >>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> >>> --- >> Tested on the system which showed the issue, this patch work fine. > So I'm going to add a Tested-by from you to it or please let me know > if you don't want me to do so. You can add. Thanks, Srinivas
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 2ca70b0b5fdc..6bbc21ca96e0 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2532,7 +2532,14 @@ static void intel_pstate_update_perf_limits(struct cpudata *cpu, int freq; freq = max_policy_perf * perf_ctl_scaling; - max_policy_perf = DIV_ROUND_UP(freq, scaling); + + if (freq == cpu->pstate.turbo_freq) + max_policy_perf = cpu->pstate.turbo_pstate; + else if (freq == cpu->pstate.max_freq) + max_policy_perf = cpu->pstate.max_pstate; + else + max_policy_perf = DIV_ROUND_UP(freq, scaling); + freq = min_policy_perf * perf_ctl_scaling; min_policy_perf = DIV_ROUND_UP(freq, scaling); }
Avoid unnecessary calculation for converting frequency to performance ratio by using a scaling factor for the maximum non turbo and turbo frequency. Here the driver already stored performance ratios for max non turbo and turbo frequency by reading from MSR_HWP_CAPABILITIES. Directly use those ratios without any calculations. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> --- drivers/cpufreq/intel_pstate.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)