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.demar...@intel.com
---

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);