Re: Sometimes I only see 3 RAPL (out of 4) Counters

[srinivas pandruvada <srinivas.pandruvada@linux.intel.com>]

On Thu, 2025-09-11 at 11:42 +0200, Rafael J. Wysocki wrote:
> +Srinivas & Rui
> 
> On Thu, Sep 11, 2025 at 2:20 AM Kenneth Crudup <kenny@panix.com>
> wrote:
> > 
> > I have a Dell XPS-9320, with a i7-1280P (family: 0x6, model: 0x9a,
> > stepping: 0x3) CPU. Sometimes I'll only see 3 RAPL counters instead
> > of
> > the normal 4. (It used to happen a lot more often, BTW):
> > 

That is because sometimes the counter for PP1 (GFX ..) is 0 during boot
and then the PMU code will ignore that. This happens when the counter
is sampled before GPU is not even started. So this is a race condition.


Thanks,
Srinivas


> > ----
> > gunzip --force --stdout /var/log/syslog* | fgrep -i rapl | fgrep
> > fixed
> > 2025-09-08T12:09:05.915989-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 3 fixed counters, 655360 ms ovfl timer
> > 2025-09-09T08:52:19.098522-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-09T17:25:24.377784-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-09T17:50:09.334140-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-10T16:42:13.259270-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 3 fixed counters, 655360 ms ovfl timer
> > 2025-09-10T16:46:36.322016-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-02T13:05:02.632218-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-02T14:07:19.683466-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-02T14:20:43.602483-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-04T13:13:38.636326-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-09-05T09:21:50.147180-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-08-29T10:57:14.419740-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-08-17T11:52:55.733943-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-08-19T07:52:30.696326-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-08-19T07:55:49.083600-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-08-20T10:53:54.601680-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-08-20T11:00:09.560496-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > 2025-08-20T11:12:30.580414-07:00 xps-9320 kernel: [    T1] RAPL
> > PMU: API
> > unit is 2^-32 Joules, 4 fixed counters, 655360 ms ovfl timer
> > ----
> > 
> > ... and it's always(?) the GPU RAPL:
> > 
> > ----
> > gunzip --force --stdout /var/log/syslog* | fgrep -i rapl | cut -d\]
> > -f2-
> > > sort -f | uniq -c
> > grep: (standard input): binary file matches
> >       18  intel_rapl_common: Found RAPL domain core
> >       36  intel_rapl_common: Found RAPL domain package
> >       18  intel_rapl_common: Found RAPL domain psys
> >       16  intel_rapl_common: Found RAPL domain uncore
> >       18  intel_rapl_msr: PL4 support detected.
> >        2  RAPL PMU: API unit is 2^-32 Joules, 3 fixed counters,
> > 655360
> > ms ovfl timer
> >       16  RAPL PMU: API unit is 2^-32 Joules, 4 fixed counters,
> > 655360
> > ms ovfl timer
> >       18  RAPL PMU: hw unit of domain package 2^-14 Joules
> >       18  RAPL PMU: hw unit of domain pp0-core 2^-14 Joules
> >       16  RAPL PMU: hw unit of domain pp1-gpu 2^-14 Joules
> >       18  RAPL PMU: hw unit of domain psys 2^-14 Joules
> > ----
> > 
> > A reboot fixes it up again (and that's if I even notice), but what
> > would
> > cause this to happen? What's the effect of it missing the RAPL
> > counter, BTW?
> > 
> > LMK if you need more info,
> > 
> > -Kenny
> > 
> > --
> > Kenneth R. Crudup / Sr. SW Engineer, Scott County Consulting,
> > Orange
> > County CA
> > 
> >