Re: [TGL-U][iGFX] Monitoring the freq of iGFX with kernel 5.10 on TGL-U i5-1145GRE

["Souza, Jose" <jose.souza@xxxxxxxxx>]

On Wed, 2022-01-12 at 10:40 +0000, Schweikhardt, Markus wrote:

> Hi Jose,
>
> What is the expected behavior of intel_gpu_top if I lock the frequency to min freq, should I always read req/act = 100/100 even if there is no gfx workload running?

That will not prevent RC6 from entering.

> -Markus
>
> -----Original Message-----
> From: Souza, Jose <jose.souza@xxxxxxxxx>
> Sent: Monday, January 10, 2022 8:14 PM
> To: Schweikhardt, Markus <markus.schweikhardt@xxxxxxxxx>; intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [Intel-gfx] [TGL-U][iGFX] Monitoring the freq of iGFX with kernel 5.10 on TGL-U i5-1145GRE
>
> On Mon, 2022-01-10 at 18:56 +0000, Schweikhardt, Markus wrote:
> > Hi all,
> >
> > I would like to monitor the frequency of the iGPU of my TGL platform
> > while running glmark2 in bursts which means glmark2 is 5secrunning and
> > 5sec not running.I disabled RC6 by echo 0 >
> > /sys/class/drm/card0/gt_rc6_enable for my tests. Furthermore, I tried
> > to lock the iGPU frequency to min, RP0 or
> > RP1 by setting e.g.
>
> Maybe is because you are running a old kerne but recent ones have /sys/class/drm/card0/power/rc6_enable that is read-only.
> There is no parameter to disable RC6 but you can change the i915 code to not enabled it and run your tests.
>
> > echo 1300 > /sys/class/drm/card0/gt_min_freq_mhz
> > echo 1300 > /sys/class/drm/card0/gt_max_freq_mhz
> > echo 1300 > /sys/class/drm/card0/gt_boost_freq_mhz.
> >
> > For frequency monitoring I am using intel_gpu_top
> > and/sys/class/drm/card0/gt_cur_freq_mhz. I am a bit confused if I compare the output becauseintel_gpu_top and/sys/class/drm/card0/gt_cur_freq_mhzshow different results.
> > These are my results if I lock gpu Frequency to 1300MHz
> >
> > ### /sys/class/drm/card0/gt_cur_freq_mhz
> > Every 0.1s: cat
> > /sys/class/drm/card0/gt_cur_freq_mhz                                                                                                      node4-
> > tglu-rvp: Mon Jan 10 20:22:59 2022
> >
> > 1300
> >
> > ### intel_gpu_top
> > root@node4-tglu-rvp:~/fGvPOC# intel_gpu_top -l
> > Freq MHz      IRQ RC6           RCS/0           BCS/0           VCS/0           VCS/1          VECS/0
> > req  act       /s   %       %  se  wa       %  se  wa       %  se  wa       %  se  wa       %  se  wa
> >    0    0       15 100    0.08   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> >    0    0       16 100    0.08   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> >    0    0       10 100    0.05   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> > 188  172     6045  86   13.22   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> > 1300 1189    44907   0   99.25   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> > 1300 1201    44702   0   99.05   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> > 1300 1182    44873   0   99.23   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> > 1300 1193    44830   0   99.08   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> > 1066  988    36336  19   80.24   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> >    6    6       10 100    0.05   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> >   13   13       15 100    0.08   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> >   13   13       16 100    0.08   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> >    0    0       13 100    0.05   0   0    0.00   0   0    0.00   0   0    0.00   0   0    0.00   0   0
> >
> > Can someone help me to understand why
> > /sys/class/drm/card0/gt_cur_freq_mhz always shows 1300MHz and intel_gpu_top (req and act)is dropping to almost 0Hz when glmark2 is not running?
> > My final goal is to figure out if render p-state transitions can impact the timeliness of my real-time workload running on a RT core.
> >
> > Kernel Info:
> > Linux node4-tglu-rvp 5.10.41-rt42-intel-ese-standard-lts-rt #1 SMP
> > PREEMPT_RT Thu Sep 23 10:21:35 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
> > Intel Yocto BKC MR3
> >
> > Thx, Markus
> > Intel Deutschland GmbH
> > Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
> > Tel: +49 89 99 8853-0, www.intel.de
> > Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
> > Chairperson of the Supervisory Board: Nicole Lau Registered Office:
> > Munich Commercial Register: Amtsgericht Muenchen HRB 186928