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

[Souza, Jose]

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 at intel.com<mailto:jose.souza at intel.com>>

Sent: Monday, January 10, 2022 8:14 PM

To: Schweikhardt, Markus <markus.schweikhardt at intel.com<mailto:markus.schweikhardt at intel.com>>; intel-gfx at lists.freedesktop.org<mailto:intel-gfx at lists.freedesktop.org>

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 at 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<http://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



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