On Mon, Sep 02, 2013 at 04:12:36PM +0200, Daniel Vetter wrote: > On Mon, Sep 02, 2013 at 02:14:12PM +0100, Chris Wilson wrote: > > On Mon, Sep 02, 2013 at 08:32:24AM +0200, Daniel Vetter wrote: > > > On Fri, Aug 30, 2013 at 08:39:46PM -0700, Ben Widawsky wrote: > > > > On Sat, Aug 31, 2013 at 12:50:30AM +0100, Chris Wilson wrote: > > > > > On Fri, Aug 30, 2013 at 04:43:54PM -0700, Ben Widawsky wrote: > > > > > > lifted from Daniel: > > > > > > pread/pwrite isn't about the object's domain at all, but purely about > > > > > > synchronizing for outstanding rendering. Replacing the call to > > > > > > set_to_gtt_domain with a wait_rendering would imo improve code > > > > > > readability. Furthermore we could pimp pread to only block for > > > > > > outstanding writes and not for reads. > > > > > > > > > > > > Since you're not the first one to trip over this: Can I volunteer you > > > > > > for a follow-up patch to fix this? > > > > > > > > > > > > Recommended-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > > > > > > Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx> > > > > > > > > > > This should fail i-g-t... > > > > > -Chris > > > > > > > > > > > > > Daniel, how have I failed your plan? > > > > > > It should work ... Since the enclosing if-block checks for !cpu domain > > > (for either reads or writes) that implies that going into the gtt domain > > > is a noop (or better should be) wrt clflushing and we only wait for > > > outstanding gpu rendering. wait_rendering is an interface that's been > > > added afterwards. Unfortunately I've failed to explain this trickery in > > > either a comment or the commit message. Bad me ;-) > > > > The issue is that in the patch pwrite is not waiting for any outstanding > > GPU reads. > > Oh right, silly me didn't spot the s/true/false/ switch Ben sneaked in. > This /should/ have been caught by the gem_concurrent_blt subtests that > exercise pwrites ... > > Ben can you please check that this indeed blew up on igt? Should fail on > any platform, no special caching mode required. Actually it won't blow up since you always set readonly = false. But it'll kill the neat read-read optimization ... -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
