From: Daniel Vetter <daniel@ffwll.ch> To: Sean Paul <sean@poorly.run> Cc: "Daniel Vetter" <daniel@ffwll.ch>, "Steven Rostedt" <rostedt@goodmis.org>, dri-devel <dri-devel@lists.freedesktop.org>, "Sean Paul" <seanpaul@chromium.org>, "Daniel Vetter" <daniel.vetter@ffwll.ch>, "David Airlie" <airlied@gmail.com>, "Jani Nikula" <jani.nikula@linux.intel.com>, "Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>, "Pekka Paalanen" <ppaalanen@gmail.com>, "Rob Clark" <robdclark@gmail.com>, "Thomas Zimmermann" <tzimmermann@suse.de>, "Ville Syrjälä" <ville.syrjala@linux.intel.com>, "Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>, "Maxime Ripard" <mripard@kernel.org>, "David Airlie" <airlied@linux.ie>, "Jonathan Corbet" <corbet@lwn.net>, linux-doc@vger.kernel.org Subject: Re: [PATCH v4] drm/trace: Buffer DRM logs in a ringbuffer accessible via debugfs Date: Mon, 27 Jan 2020 09:58:55 +0100 [thread overview] Message-ID: <20200127085855.GS43062@phenom.ffwll.local> (raw) In-Reply-To: <CAMavQKKByEeG=i95nccVQDLNUjKFO+rkcGMSv0hG_SyyZvv6Pw@mail.gmail.com> On Wed, Jan 22, 2020 at 10:39:15AM -0500, Sean Paul wrote: > On Wed, Jan 22, 2020 at 3:06 AM Daniel Vetter <daniel@ffwll.ch> wrote: > > > > On Mon, Jan 20, 2020 at 01:56:21PM -0500, Steven Rostedt wrote: > > > On Thu, 16 Jan 2020 07:27:22 +0100 > > > Daniel Vetter <daniel@ffwll.ch> wrote: > > > > > > > On Tue, Jan 14, 2020 at 12:21:43PM -0500, Sean Paul wrote: > > > > > From: Sean Paul <seanpaul@chromium.org> > > > > > > > > > > This patch uses a ring_buffer to keep a "flight recorder" (name credit Weston) > > > > > of DRM logs for a specified set of debug categories. The user writes a > > > > > bitmask of debug categories to the "trace_mask" node and can read log > > > > > messages from the "trace" node. > > > > > > > > > > These nodes currently exist in debugfs under the dri directory. I > > > > > intended on exposing all of this through tracefs originally, but the > > > > > tracefs entry points are not exposed, so there's no way to create > > > > > tracefs files from drivers at the moment. I think it would be a > > > > > worthwhile endeavour, but one requiring more time and conversation to > > > > > ensure the drm traces fit somewhere sensible. > > > > > > > > Hm, since the idea is to ship this in production environments debugfs is > > > > out. sysfs is also kinda the wrong thing, so maybe trying to get this > > > > stuffed into tracefs is actually the way to go? > > > > > > > > > > Why not use normal tracepoints and the tracing infrastructure? You can > > > add your own instance as rasdaemon does, which isn't affected by other > > > tracing. There's code now to even create these instances and enable and > > > disable events from within the kernel. > > > > > > https://lore.kernel.org/lkml/1574276919-11119-1-git-send-email-divya.indi@oracle.com/ > > > > Hm, without looking at the details this indeed seems like the thing we > > want ... Sean? > > Ohh indeed, I think we could make this work. Thanks for the pointer, Steven! > > The only item that needs sorting is: how does userspace select which > debug events are traced. I think we could solve both with another > module parameter to sit beside drm.debug with the same semantics (call > it drm.trace)? Yeah if there's no official way (in tracefs) for this drm.trace sounds reasonable. -Daniel > > > Sean > > > -Daniel > > > > > > > > As this is tracefs, you can mount it without even compiling in debugfs. > > > > > > -- Steve > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
WARNING: multiple messages have this Message-ID (diff)
From: Daniel Vetter <daniel@ffwll.ch> To: Sean Paul <sean@poorly.run> Cc: linux-doc@vger.kernel.org, Thomas Zimmermann <tzimmermann@suse.de>, Jonathan Corbet <corbet@lwn.net>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel.vetter@ffwll.ch>, dri-devel <dri-devel@lists.freedesktop.org>, Sean Paul <seanpaul@chromium.org>, Steven Rostedt <rostedt@goodmis.org> Subject: Re: [PATCH v4] drm/trace: Buffer DRM logs in a ringbuffer accessible via debugfs Date: Mon, 27 Jan 2020 09:58:55 +0100 [thread overview] Message-ID: <20200127085855.GS43062@phenom.ffwll.local> (raw) In-Reply-To: <CAMavQKKByEeG=i95nccVQDLNUjKFO+rkcGMSv0hG_SyyZvv6Pw@mail.gmail.com> On Wed, Jan 22, 2020 at 10:39:15AM -0500, Sean Paul wrote: > On Wed, Jan 22, 2020 at 3:06 AM Daniel Vetter <daniel@ffwll.ch> wrote: > > > > On Mon, Jan 20, 2020 at 01:56:21PM -0500, Steven Rostedt wrote: > > > On Thu, 16 Jan 2020 07:27:22 +0100 > > > Daniel Vetter <daniel@ffwll.ch> wrote: > > > > > > > On Tue, Jan 14, 2020 at 12:21:43PM -0500, Sean Paul wrote: > > > > > From: Sean Paul <seanpaul@chromium.org> > > > > > > > > > > This patch uses a ring_buffer to keep a "flight recorder" (name credit Weston) > > > > > of DRM logs for a specified set of debug categories. The user writes a > > > > > bitmask of debug categories to the "trace_mask" node and can read log > > > > > messages from the "trace" node. > > > > > > > > > > These nodes currently exist in debugfs under the dri directory. I > > > > > intended on exposing all of this through tracefs originally, but the > > > > > tracefs entry points are not exposed, so there's no way to create > > > > > tracefs files from drivers at the moment. I think it would be a > > > > > worthwhile endeavour, but one requiring more time and conversation to > > > > > ensure the drm traces fit somewhere sensible. > > > > > > > > Hm, since the idea is to ship this in production environments debugfs is > > > > out. sysfs is also kinda the wrong thing, so maybe trying to get this > > > > stuffed into tracefs is actually the way to go? > > > > > > > > > > Why not use normal tracepoints and the tracing infrastructure? You can > > > add your own instance as rasdaemon does, which isn't affected by other > > > tracing. There's code now to even create these instances and enable and > > > disable events from within the kernel. > > > > > > https://lore.kernel.org/lkml/1574276919-11119-1-git-send-email-divya.indi@oracle.com/ > > > > Hm, without looking at the details this indeed seems like the thing we > > want ... Sean? > > Ohh indeed, I think we could make this work. Thanks for the pointer, Steven! > > The only item that needs sorting is: how does userspace select which > debug events are traced. I think we could solve both with another > module parameter to sit beside drm.debug with the same semantics (call > it drm.trace)? Yeah if there's no official way (in tracefs) for this drm.trace sounds reasonable. -Daniel > > > Sean > > > -Daniel > > > > > > > > As this is tracefs, you can mount it without even compiling in debugfs. > > > > > > -- Steve > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-01-27 8:59 UTC|newest] Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-14 17:21 [PATCH v4] drm/trace: Buffer DRM logs in a ringbuffer accessible via debugfs Sean Paul 2020-01-14 17:21 ` Sean Paul 2020-01-14 17:30 ` Steven Rostedt 2020-01-14 17:30 ` Steven Rostedt 2020-01-15 9:25 ` Joonas Lahtinen 2020-01-15 10:14 ` Pekka Paalanen 2020-01-15 10:14 ` Pekka Paalanen 2020-01-15 13:31 ` Sean Paul 2020-01-15 13:31 ` Sean Paul 2020-01-15 10:28 ` Jani Nikula 2020-01-15 10:28 ` Jani Nikula 2020-01-15 13:34 ` Sean Paul 2020-01-15 13:34 ` Sean Paul 2020-01-15 10:36 ` Chris Wilson 2020-01-15 10:36 ` Chris Wilson 2020-01-15 13:41 ` Sean Paul 2020-01-15 13:41 ` Sean Paul 2020-01-15 14:01 ` Chris Wilson 2020-01-15 14:01 ` Chris Wilson 2020-01-15 14:21 ` Sean Paul 2020-01-15 14:21 ` Sean Paul 2020-01-15 17:38 ` Chris Wilson 2020-01-15 17:38 ` Chris Wilson 2020-01-15 18:29 ` Sean Paul 2020-01-15 18:29 ` Sean Paul 2020-01-16 6:27 ` Daniel Vetter 2020-01-16 6:27 ` Daniel Vetter 2020-01-20 18:56 ` Steven Rostedt 2020-01-20 18:56 ` Steven Rostedt 2020-01-22 8:06 ` Daniel Vetter 2020-01-22 8:06 ` Daniel Vetter 2020-01-22 15:39 ` Sean Paul 2020-01-22 15:39 ` Sean Paul 2020-01-27 8:58 ` Daniel Vetter [this message] 2020-01-27 8:58 ` Daniel Vetter
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