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Date: Wed, 18 Jun 2014 18:44:40 -0700
From: Greg KH <gregkh@linuxfoundation.org>
To: Rob Clark <robdclark@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>,
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        Sumit Semwal <sumit.semwal@linaro.org>,
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Subject: Re: [REPOST PATCH 1/8] fence: dma-buf cross-device synchronization
 (v17)
Message-ID: <20140619014440.GA13493@kroah.com>
References: <20140618102957.15728.43525.stgit@patser>
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On Wed, Jun 18, 2014 at 09:23:06PM -0400, Rob Clark wrote:
> On Wed, Jun 18, 2014 at 9:13 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Wed, Jun 18, 2014 at 12:36:54PM +0200, Maarten Lankhorst wrote:
> >> +#define CREATE_TRACE_POINTS
> >> +#include <trace/events/fence.h>
> >> +
> >> +EXPORT_TRACEPOINT_SYMBOL(fence_annotate_wait_on);
> >> +EXPORT_TRACEPOINT_SYMBOL(fence_emit);
> >
> > Are you really willing to live with these as tracepoints for forever?
> > What is the use of them in debugging?  Was it just for debugging the
> > fence code, or for something else?
> 
> fwiw, the goal is something like this:
> 
> http://people.freedesktop.org/~robclark/perf-supertuxkart.svg
> 
> but without needing to make perf understand each driver's custom trace events
> 
> (from: http://bloggingthemonkey.blogspot.com/2013/09/freedreno-update-moar-fps.html
> )

Will these tracepoints provide something like that?  If so, great, but I
want to make sure as these now become a user/kernel ABI that you can not
break.

thanks,

greg k-h