Re: [PATCH] perf/x86/rapl: Fix PP1 event for Intel Meteor/Lunar Lake

[Lucas De Marchi]

On Thu, Feb 20, 2025 at 11:47:21AM -0500, Liang, Kan wrote:
> On 2025-02-20 10:36 a.m., Lucas De Marchi wrote:
> > On some boots the read of MSR_PP1_ENERGY_STATUS msr returns 0, causing
> > perf_msr_probe() to make the power/events/energy-gpu event non-visible.
> > When that happens, the msr always read 0 until the graphics module (i915
> > for Meteor Lake, xe for Lunar Lake) is loaded. Then it starts returning
> > something different and re-loading the rapl module "fixes" it.
> >
> > This is tested on the following platforms with the fail rates before
> > this patch:
> >
> > 	Alder Lake S	0/20
> > 	Arrow Lake H	0/20
> > 	Lunar Lake M	8/20
> > 	Meteor Lake U	6/20
> > 	Raptor Lake P	4/20
> > 	Raptor Lake S	0/20
> >
> > For those platforms failing, use a separate msr list with .no_check
> > set so it doesn't check the runtime value to create the event - it will
> > just return 0 until the i915/xe module initializes the GPU.
> >
> > The issue https://github.com/ulissesf/qmassa/issues/4 is workarounded by
> > reading the MSR directly since it works after xe is loaded, but the
> > issue with not having the perf event is still there.
> >
> > Closes: https://github.com/ulissesf/qmassa/issues/4
> > Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4241
> > Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx
> > ---
> >
> > Maybe a clearer alternative is to just move all the platforms after
> > RAPTORLAKE with a gpu to use the new msr list.
> >
> >  arch/x86/events/rapl.c | 26 ++++++++++++++++++++++----
> >  1 file changed, 22 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
> > index 4952faf03e82d..18e324b8fa82c 100644
> > --- a/arch/x86/events/rapl.c
> > +++ b/arch/x86/events/rapl.c
> > @@ -588,6 +588,14 @@ static struct perf_msr intel_rapl_spr_msrs[] = {
> >  	[PERF_RAPL_PSYS] = { MSR_PLATFORM_ENERGY_STATUS, &rapl_events_psys_group,  test_msr, true, RAPL_MSR_MASK },
> >  };
> >
> > +static struct perf_msr intel_rapl_mtl_msrs[] = {
> > +	[PERF_RAPL_PP0]  = { MSR_PP0_ENERGY_STATUS,      &rapl_events_cores_group, test_msr, false, RAPL_MSR_MASK },
> > +	[PERF_RAPL_PKG]  = { MSR_PKG_ENERGY_STATUS,      &rapl_events_pkg_group,   test_msr, false, RAPL_MSR_MASK },
> > +	[PERF_RAPL_RAM]  = { MSR_DRAM_ENERGY_STATUS,     &rapl_events_ram_group,   test_msr, false, RAPL_MSR_MASK },
> > +	[PERF_RAPL_PP1]  = { MSR_PP1_ENERGY_STATUS,      &rapl_events_gpu_group,   test_msr, true,  RAPL_MSR_MASK },
> > +	[PERF_RAPL_PSYS] = { MSR_PLATFORM_ENERGY_STATUS, &rapl_events_psys_group,  test_msr, false, RAPL_MSR_MASK },
> > +};
> > +
> >  /*
> >   * Force to PERF_RAPL_PKG_EVENTS_MAX size due to:
> >   * - perf_msr_probe(PERF_RAPL_PKG_EVENTS_MAX)
> > @@ -826,6 +834,16 @@ static struct rapl_model model_spr = {
> >  	.rapl_pkg_msrs	= intel_rapl_spr_msrs,
> >  };
> >
> > +static struct rapl_model model_rpl = {
> > +	.pkg_events	= BIT(PERF_RAPL_PP0) |
> > +			  BIT(PERF_RAPL_PKG) |
> > +			  BIT(PERF_RAPL_RAM) |
> > +			  BIT(PERF_RAPL_PP1) |
> > +			  BIT(PERF_RAPL_PSYS),
> > +	.msr_power_unit = MSR_RAPL_POWER_UNIT,
> > +	.rapl_pkg_msrs  = intel_rapl_mtl_msrs,
>
> It's better to make the name consistent, e.g., intel_rapl_rpl_msrs.

that's what happens when you decide to test on RPL just before sending
and forget to rename all the variables. Thanks for noticing.

I will rename it on next version if we decide to keep this approach.
Also please let me know what you think about moving arl and other rpl to
model_rpl, too.

thanks
Lucas De Marchi

> Thanks,
> Kan
> > +};
> > +
> >  static struct rapl_model model_amd_hygon = {
> >  	.pkg_events	= BIT(PERF_RAPL_PKG),
> >  	.core_events	= BIT(PERF_RAPL_CORE),
> > @@ -873,13 +891,13 @@ static const struct x86_cpu_id rapl_model_match[] __initconst = {
> >  	X86_MATCH_VFM(INTEL_SAPPHIRERAPIDS_X,	&model_spr),
> >  	X86_MATCH_VFM(INTEL_EMERALDRAPIDS_X,	&model_spr),
> >  	X86_MATCH_VFM(INTEL_RAPTORLAKE,		&model_skl),
> > -	X86_MATCH_VFM(INTEL_RAPTORLAKE_P,	&model_skl),
> > +	X86_MATCH_VFM(INTEL_RAPTORLAKE_P,	&model_rpl),
> >  	X86_MATCH_VFM(INTEL_RAPTORLAKE_S,	&model_skl),
> > -	X86_MATCH_VFM(INTEL_METEORLAKE,		&model_skl),
> > -	X86_MATCH_VFM(INTEL_METEORLAKE_L,	&model_skl),
> > +	X86_MATCH_VFM(INTEL_METEORLAKE,		&model_rpl),
> > +	X86_MATCH_VFM(INTEL_METEORLAKE_L,	&model_rpl),
> >  	X86_MATCH_VFM(INTEL_ARROWLAKE_H,	&model_skl),
> >  	X86_MATCH_VFM(INTEL_ARROWLAKE,		&model_skl),
> > -	X86_MATCH_VFM(INTEL_LUNARLAKE_M,	&model_skl),
> > +	X86_MATCH_VFM(INTEL_LUNARLAKE_M,	&model_rpl),
> >  	{},
> >  };
> >  MODULE_DEVICE_TABLE(x86cpu, rapl_model_match);