AMD General > -----Original Message----- > From: Alex Deucher <[email protected]> > Sent: Friday, August 14, 2026 8:51 AM > To: Boqun Feng <[email protected]> > Cc: [email protected]; Mark Janes <[email protected]>; Feng, > Kenneth <[email protected]>; Deucher, Alexander > <[email protected]>; Koenig, Christian > <[email protected]>; David Airlie <[email protected]>; Simona > Vetter <[email protected]>; Lazar, Lijo <[email protected]>; Kamal, Asad > <[email protected]>; Wang, Yang(Kevin) <[email protected]>; > Hosur, Priya <[email protected]>; M, Mythila <[email protected]>; > Limonciello, Mario <[email protected]>; dri- > [email protected]; [email protected]; Umio Yasuno > <[email protected]> > Subject: Re: [PATCH] drm/amd/pm: Fix incorrect avg vcn utilization in > gpu_metrics > > On Thu, Aug 13, 2026 at 6:25 PM Boqun Feng <[email protected]> wrote: > > > > On Thu, Aug 13, 2026 at 06:01:47PM -0400, Alex Deucher wrote: > > > On Thu, Aug 13, 2026 at 5:36 PM Boqun Feng <[email protected]> wrote: > > > > > > > > On Wed, Aug 05, 2026 at 07:02:21AM -0700, Boqun Feng wrote: > > > > > In a Strix Halo system, a >100 average_vcn_activity in > > > > > gpu_metrics can be observed by running the following command: > > > > > > > > > > ffmpeg -hwaccel vappi -vappi_device /dev/dri/renderD128 -i \ > > > > > ~/sample-10s.mp4 -vf hwupload,scale_vappi=format=nv12 -c:v \ > > > > > h264_vappi /tmp/output.mp4 > > > > > > > > > > This is incorrect because the value is supposed to be in [0-100] > > > > > range. > > > > > > > > > > The cause of the issue is that the metrics.VcnActivity reported > > > > > by > > > > > smu_cmn_get_metrics_table() is a permyriad value instead of a > > > > > percentage value (e.g. smu_v14_0_0_get_smu_metrics_data() has a > > > > > division by 100 to report the vcn_busy_percent). Therefore fix > > > > > this by applying the same division in smu_v14_0_0_get_gpu_metrics(). > > > > > > I think this is correct as is. smu_v14_0_0_get_smu_metrics_data() > > > is used to fetch data for standardized formats like hwmon while > > > smu_v14_0_0_get_gpu_metrics() is for dumping the raw metrics data. > > > > > > > Well, then kgd_pp_interface.h needs some help? > > > > struct gpu_metrics_v3_0 { > > ... > > /* Utilization */ > > /* time filtered GFX busy % [0-100] */ > > uint16_t average_gfx_activity; > > /* time filtered VCN busy % [0-100] */ > > uint16_t average_vcn_activity; > > ... > > } > > > > Clearly it's not true. > > That was likely copy and pasted from the firmware interface > (smu14_driver_if_v14_0_0.h): > uint16_t VcnActivity; //Time filtered VCN busy % [0-100] > > Other generations seem to do the same thing (raw data in metrics table > and % in the hwmon type interfaces). E.g., smu_v13_0_4_ppt.c: > smu_v13_0_4_get_gpu_metrics() > gpu_metrics->average_mm_activity = metrics.UvdActivity; vs > smu_v13_0_4_get_smu_metrics_data(): > *value = metrics->UvdActivity / 100;
For SMU 14.0.0, the VCN activity value returned from PMFW ranges from 0 to 10000, and the driver shall divide this value by 100 before reporting it. This scaling does **not** apply to GFX activity. Best Regards, Kevin > > Alex > > > > > [Cc amdgpu_top] > > > > Regards, > > Boqun > > > > > Alex > > > > > > > > > > > > > Reported-by: Mark Janes <[email protected]> > > > > > Signed-off-by: Boqun Feng <[email protected]> > > > > > > > > Ping? > > > > > > > > Regards, > > > > Boqun > > > > > > > > > --- > > > > > drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c | 3 ++- > > > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git > > > > > a/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c > > > > > b/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c > > > > > index 568665265a13..1058338344b0 100644 > > > > > --- a/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c > > > > > +++ b/drivers/gpu/drm/amd/pm/swsmu/smu14/smu_v14_0_0_ppt.c > > > > > @@ -566,7 +566,8 @@ static ssize_t > smu_v14_0_0_get_gpu_metrics(struct smu_context *smu, > > > > > gpu_metrics->temperature_skin = metrics.SkinTemp; > > > > > > > > > > gpu_metrics->average_gfx_activity = metrics.GfxActivity; > > > > > - gpu_metrics->average_vcn_activity = metrics.VcnActivity; > > > > > + /* metrics.VcnActivity is permyriad, convert it to percentage. > > > > > */ > > > > > + gpu_metrics->average_vcn_activity = metrics.VcnActivity / > > > > > + 100; > > > > > memcpy(&gpu_metrics->average_ipu_activity[0], > > > > > &metrics.IpuBusy[0], > > > > > sizeof(uint16_t) * 8); > > > > > -- > > > > > 2.50.1 (Apple Git-155) > > > > >
