Re: [REPOST PATCH 1/8] fence: dma-buf cross-device synchronization (v17)

[Greg KH <gregkh@linuxfoundation.org>]

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