From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 838F4C433DF for ; Wed, 12 Aug 2020 15:19:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 696A520829 for ; Wed, 12 Aug 2020 15:19:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726660AbgHLPTY convert rfc822-to-8bit (ORCPT ); Wed, 12 Aug 2020 11:19:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:41500 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726489AbgHLPTX (ORCPT ); Wed, 12 Aug 2020 11:19:23 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DC83C207F7; Wed, 12 Aug 2020 15:19:21 +0000 (UTC) Date: Wed, 12 Aug 2020 11:19:20 -0400 From: Steven Rostedt To: Christian =?UTF-8?B?S8O2bmln?= Cc: christian.koenig@amd.com, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Shashank.Sharma@amd.com, daniel.vetter@ffwll.ch, alexander.deucher@amd.com Subject: Re: [PATCH] drm/amdgpu: adjust the pid in the grab_id trace point Message-ID: <20200812111920.06efa663@oasis.local.home> In-Reply-To: References: <20200807133658.1866-1-christian.koenig@amd.com> <20200807133658.1866-2-christian.koenig@amd.com> <20200812141755.GA8136@home.goodmis.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 12 Aug 2020 16:36:36 +0200 Christian König 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 > >> --- > >> 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