"Pandruvada, Srinivas" <srinivas.pandruv...@intel.com> writes:
> On Sat, 2018-07-28 at 07:14 -0700, Srinivas Pandruvada wrote: >> On Fri, 2018-07-27 at 22:34 -0700, Francisco Jerez wrote: >> > Srinivas Pandruvada <srinivas.pandruv...@linux.intel.com> writes: >> > >> > > Enable HWP boost on Skylake server and workstations. >> > > >> > >> > Please revert this series, it led to significant energy usage and >> > graphics performance regressions [1]. >> >> Which SKX platform is targeted to graphics? > There are some Xeon E3, which is using SKL desktop CPUID. > Do you have a SKL desktop with FADT pm profile > acpi_gbl_FADT.preferred_profile == PM_DESKTOP? You can take acpidump > and check. > > Also what is > /sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost > Eero is the one that reproduced the regressions -- Can you get Srinivas this information from your system? Thank you. > Thanks, > Srinivas > >> >> > The reasons are roughly the ones >> > we discussed by e-mail off-list last April: This causes the >> > intel_pstate >> > driver to decrease the EPP to zero >> >> No. You didn't check this series. We are not using EPP at all. >> The boost mechanism used here is not boost to max. >> >> Thanks, >> Srinivas >> >> > when the workload blocks on IO >> > frequently enough, which for the regressing benchmarks detailed in >> > [1] >> > is a symptom of the workload being heavily IO-bound, which means >> > they >> > won't benefit at all from the EPP boost since they aren't >> > significantly >> > CPU-bound, and they will suffer a decrease in parallelism due to >> > the >> > active CPU core using a larger fraction of the TDP in order to >> > achieve >> > the same work, causing the GPU to have a lower power budget >> > available, >> > leading to a decrease in system performance. >> > >> > You may want to give a shot to my previous suggestion of using [2] >> > in >> > order to detect whether the system is IO-bound, which you can use >> > as >> > an >> > indicator that the optimization implemented in this series cannot >> > possibly improve performance and can be expected to hurt energy >> > usage. >> > >> > Thanks. >> > >> > [1] https://bugs.freedesktop.org/show_bug.cgi?id=107410 >> > [2] https://patchwork.kernel.org/patch/10312259/ >> > >> > > Reported-by: Mel Gorman <mgor...@techsingularity.net> >> > > Tested-by: Giovanni Gherdovich <ggherdov...@suse.cz> >> > > Signed-off-by: Srinivas Pandruvada <srinivas.pandruv...@linux.int >> > > el >> > > .com> >> > > --- >> > > drivers/cpufreq/intel_pstate.c | 10 ++++++++++ >> > > 1 file changed, 10 insertions(+) >> > > >> > > diff --git a/drivers/cpufreq/intel_pstate.c >> > > b/drivers/cpufreq/intel_pstate.c >> > > index 70bf63bb4e0e..01c8da1f99db 100644 >> > > --- a/drivers/cpufreq/intel_pstate.c >> > > +++ b/drivers/cpufreq/intel_pstate.c >> > > @@ -1794,6 +1794,12 @@ static const struct x86_cpu_id >> > > intel_pstate_cpu_ee_disable_ids[] = { >> > > {} >> > > }; >> > > >> > > +static const struct x86_cpu_id intel_pstate_hwp_boost_ids[] >> > > __initconst = { >> > > + ICPU(INTEL_FAM6_SKYLAKE_X, core_funcs), >> > > + ICPU(INTEL_FAM6_SKYLAKE_DESKTOP, core_funcs), >> > > + {} >> > > +}; >> > > + >> > > static int intel_pstate_init_cpu(unsigned int cpunum) >> > > { >> > > struct cpudata *cpu; >> > > @@ -1824,6 +1830,10 @@ static int intel_pstate_init_cpu(unsigned >> > > int cpunum) >> > > intel_pstate_disable_ee(cpunum); >> > > >> > > intel_pstate_hwp_enable(cpu); >> > > + >> > > + id = x86_match_cpu(intel_pstate_hwp_boost_ids); >> > > + if (id) >> > > + hwp_boost = true; >> > > } >> > > >> > > intel_pstate_get_cpu_pstates(cpu); >> > > -- >> > > 2.13.6
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