On Thu, 2020-12-17 at 16:24 +0100, Rafael J. Wysocki wrote: > On Thu, Dec 17, 2020 at 4:21 PM Srinivas Pandruvada > <srinivas.pandruv...@linux.intel.com> wrote: > > > > On Thu, 2020-12-17 at 16:12 +0100, Rafael J. Wysocki wrote: > > > On Thursday, December 17, 2020 3:23:44 PM CET Srinivas Pandruvada > > > wrote: > > > > On Thu, 2020-12-17 at 06:19 -0800, Srinivas Pandruvada wrote: > > > > > On Thu, 2020-12-17 at 14:58 +0100, Rafael J. Wysocki wrote: > > > > > > On Thu, Dec 17, 2020 at 11:44 AM Srinivas Pandruvada > > > > > > <srinivas.pandruv...@linux.intel.com> wrote: > > > > > > > > > > > > > > This change tries to address an issue, when BIOS disabled > > > > > > > turbo > > > > > > > but HWP_CAP guaranteed is changed later and user space > > > > > > > wants > > > > > > > to > > > > > > > take > > > > > > > advantage of this increased guaranteed performance. > > > > > > > > > > > > > > The HWP_CAP.GUARANTEED value is not a static value. It > > > > > > > can be > > > > > > > changed > > > > > > > by some out of band agent or during Intel Speed Select > > > > > > > performance > > > > > > > level change. The HWP_CAP.MAX still shows max possible > > > > > > > performance > > > > > > > when > > > > > > > BIOS disabled turbo. So guaranteed can still change as > > > > > > > long > > > > > > > as > > > > > > > this > > > > > > > is > > > > > > > same or below HWP_CAP.MAX. > > > > > > > > > > > > > > When guaranteed is changed, the sysfs base_frequency > > > > > > > attributes > > > > > > > shows > > > > > > > the latest guaranteed frequency. This attribute can be > > > > > > > used > > > > > > > by > > > > > > > user > > > > > > > space software to update scaling min/max frequency. > > > > > > > > > > > > > > Currently the setpolicy callback already uses the latest > > > > > > > HWP_CAP > > > > > > > values when setting HWP_REQ. But the verify callback will > > > > > > > still > > > > > > > restrict > > > > > > > the user settings to the to old guaranteed value. So if > > > > > > > the > > > > > > > guaranteed > > > > > > > is increased, user space can't take advantage of it. > > > > > > > > > > > > > > To solve this similar to setpolicy callback, read the > > > > > > > latest > > > > > > > HWP_CAP > > > > > > > values and use it to restrict the maximum setting. This > > > > > > > is > > > > > > > done > > > > > > > by > > > > > > > calling intel_pstate_get_hwp_max(), which already > > > > > > > accounts > > > > > > > for > > > > > > > user > > > > > > > and BIOS turbo disable to get the current max > > > > > > > performance. > > > > > > > > > > > > > > This issue is side effect of fixing the issue of scaling > > > > > > > frequency > > > > > > > limits by the > > > > > > > 'commit eacc9c5a927e ("cpufreq: intel_pstate: > > > > > > > Fix intel_pstate_get_hwp_max() for turbo disabled")' > > > > > > > The fix resulted in correct setting of reduced scaling > > > > > > > frequencies, > > > > > > > but this resulted in capping HWP.REQ to > > > > > > > HWP_CAP.GUARANTEED in > > > > > > > this > > > > > > > case. > > > > > > > > > > > > > > Cc: 5.8+ <sta...@vger.kernel.org> # 5.8+ > > > > > > > Signed-off-by: Srinivas Pandruvada < > > > > > > > srinivas.pandruv...@linux.intel.com> > > > > > > > --- > > > > > > > drivers/cpufreq/intel_pstate.c | 6 ++++++ > > > > > > > 1 file changed, 6 insertions(+) > > > > > > > > > > > > > > diff --git a/drivers/cpufreq/intel_pstate.c > > > > > > > b/drivers/cpufreq/intel_pstate.c > > > > > > > index 2a4db856222f..7081d1edb22b 100644 > > > > > > > --- a/drivers/cpufreq/intel_pstate.c > > > > > > > +++ b/drivers/cpufreq/intel_pstate.c > > > > > > > @@ -2199,6 +2199,12 @@ static void > > > > > > > intel_pstate_clear_update_util_hook(unsigned int cpu) > > > > > > > > > > > > > > static int intel_pstate_get_max_freq(struct cpudata > > > > > > > *cpu) > > > > > > > { > > > > > > > + if (hwp_active) { > > > > > > > + int turbo_max, max_state; > > > > > > > + > > > > > > > + intel_pstate_get_hwp_max(cpu->cpu, > > > > > > > &turbo_max, > > > > > > > &max_state); > > > > > > > > > > > > This would cause intel_pstate_get_hwp_max() to be called > > > > > > twice > > > > > > in > > > > > > intel_pstate_update_perf_limits() which is not perfect. > > > > > > > > > > We can optimize by using cached value. > > > > > > > > > > > > > > > diff --git a/drivers/cpufreq/intel_pstate.c > > > > > b/drivers/cpufreq/intel_pstate.c > > > > > index 7081d1edb22b..d345c9ef240c 100644 > > > > > --- a/drivers/cpufreq/intel_pstate.c > > > > > +++ b/drivers/cpufreq/intel_pstate.c > > > > > @@ -2223,7 +2223,11 @@ static void > > > > > intel_pstate_update_perf_limits(struct cpudata *cpu, > > > > > * rather than pure ratios. > > > > > */ > > > > > if (hwp_active) { > > > > > - intel_pstate_get_hwp_max(cpu->cpu, > > > > > &turbo_max, > > > > > &max_state); > > > > > + if (global.no_turbo || global.turbo_disabled) > > > > > + max_state = HWP_GUARANTEED_PERF(cpu- > > > > > > hwp_cap_cached); > > > > > + else > > > > > + max_state = HWP_HIGHEST_PERF(cpu- > > > > > > hwp_cap_cached); > > > > Can use ternary operator instead of if..else. to further > > > > simplify. > > > > > > > > > + turbo_max = HWP_HIGHEST_PERF(cpu- > > > > > >hwp_cached); > > > > > } else { > > > > > max_state = global.no_turbo || > > > > > global.turbo_disabled > > > > > ? > > > > > cpu->pstate.max_pstate : cpu- > > > > > > pstate.turbo_pstate; > > > > > > Well, would something like the patch below work? > > > > > > --- > > > drivers/cpufreq/intel_pstate.c | 16 +++++++++++++--- > > > 1 file changed, 13 insertions(+), 3 deletions(-) > > > > > > Index: linux-pm/drivers/cpufreq/intel_pstate.c > > > ================================================================= > > > == > > > --- linux-pm.orig/drivers/cpufreq/intel_pstate.c > > > +++ linux-pm/drivers/cpufreq/intel_pstate.c > > > @@ -2207,9 +2207,9 @@ static void intel_pstate_update_perf_lim > > > unsigned int > > > policy_min, > > > unsigned int > > > policy_max) > > > { > > > - int max_freq = intel_pstate_get_max_freq(cpu); > > > int32_t max_policy_perf, min_policy_perf; > > > int max_state, turbo_max; > > > + int max_freq; > > > > > > /* > > > * HWP needs some special consideration, because on BDX > > > the > > > @@ -2223,6 +2223,7 @@ static void intel_pstate_update_perf_lim > > > cpu->pstate.max_pstate : cpu- > > > > pstate.turbo_pstate; > > > turbo_max = cpu->pstate.turbo_pstate; > > > } > > > + max_freq = max_state * cpu->pstate.scaling; > > > > > > max_policy_perf = max_state * policy_max / max_freq; > > > if (policy_max == policy_min) { > > > @@ -2325,9 +2326,18 @@ static void intel_pstate_adjust_policy_m > > > static void intel_pstate_verify_cpu_policy(struct cpudata *cpu, > > > struct > > > cpufreq_policy_data > > > *policy) > > > { > > > + int max_freq; > > > + > > > update_turbo_state(); > > > - cpufreq_verify_within_limits(policy, policy- > > > > cpuinfo.min_freq, > > > - > > > intel_pstate_get_max_freq(cpu)); > > > + if (hwp_active) { > > > + int max_state, turbo_max; > > > + > > > + intel_pstate_get_hwp_max(cpu->cpu, &turbo_max, > > > &max_state); > > > + max_freq = max_state * cpu->pstate.scaling; > > > + } else { > > > + max_freq = intel_pstate_get_max_freq(cpu); > > > + } > > > + cpufreq_verify_within_limits(policy, policy- > > > > cpuinfo.min_freq, max_freq); > > > > > > intel_pstate_adjust_policy_max(cpu, policy); > > > } > > > > > Should work. > > I will test this patch and let you know once I get the system. > > Please do, thank you!
This works. Please check if you can submit a change for this. Thanks, Srinivas