On Wed, 12 Aug 2020 16:36:36 +0200 Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote: > Am 12.08.20 um 16:17 schrieb Steven Rostedt: > > On Fri, Aug 07, 2020 at 03:36:58PM +0200, Christian König wrote: > >> Trace something useful instead of the pid of a kernel thread here. > >> > >> Signed-off-by: Christian König <christian.koenig@xxxxxxx> > >> --- > >> drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h > >> index 5da20fc166d9..07f99ef69d91 100644 > >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h > >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h > >> @@ -228,6 +228,7 @@ TRACE_EVENT(amdgpu_vm_grab_id, > >> ), > >> > >> TP_fast_assign( > >> + __entry->ent.pid = vm->task_info.pid; > > If the ent.pid is not the pid you are interested in for this trace event, just > > add a "pid" field to the trace event and place it there. Do not modify the > > generic pid that is recorded, as we would like that to be consistent for all > > trace events. > > The problem my userspace guys have is that this doesn't work with > "trace-cmd -P $pid". > > But I think I can teach them how filters work :) Yep, trace-cmd record -e event -f "pid == $pid" > > > The "ent.pid" turns into "common_pid" in the field, leaving "pid" free to use. > > Other trace events (like sched_waking) record a pid field that is not the same > > as the pid of the executing task. > > Yes, we thought about this alternative as well. > > > The "ent.pid" should always be the pid of the task that executed the event. > > Why? For the case here we just execute a work item in the background for > an userspace process. > > Tracing the pid of the worker pool which executes it doesn't seem to > make to much sense. Maybe not for you, but it does for me. All trace events show what happened when it happened and who executed it. I like to see what worker threads are executing. I may filter on the worker thread, and by changing the ent.pid, I wont see what it is doing. That said, I think I may add a feature to a trace evnt for a special filter to say, "test field to the set_event_pid", and if it exists in that file to include that event in the filtered trace. This would include sched_waking trace events as well. That way "trace-cmd record -P $pid" will still work for your case. -- Steve _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
