On Fri, Nov 01, 2013 at 11:52:48AM -0700, Ben Widawsky wrote: > On Fri, Nov 01, 2013 at 07:47:37PM +0100, Daniel Vetter wrote: > > On Fri, Nov 01, 2013 at 11:44:40AM -0700, Ben Widawsky wrote: > > > On Fri, Nov 01, 2013 at 07:42:59PM +0100, Daniel Vetter wrote: > > > > On Fri, Nov 01, 2013 at 09:18:51AM -0700, Ben Widawsky wrote: > > > > > On Fri, Nov 01, 2013 at 05:08:17PM +0100, Daniel Vetter wrote: > > > > > > On Fri, Nov 01, 2013 at 12:53:42PM +0000, oscar.mateo@xxxxxxxxx wrote: > > > > > > > From: Oscar Mateo <oscar.mateo@xxxxxxxxx> > > > > > > > > > > > > > > We don't want a previously used object to be freed in the middle of a > > > > > > > before/after object counting operation (or we would get a "-1 objects > > > > > > > leaked" message). We have seen this happening, e.g., when a context > > > > > > > from a previous run dies, but its backing object is alive waiting for > > > > > > > a retire_work to kick in. > > > > > > > > > > > > > > Signed-off-by: Oscar Mateo <oscar.mateo@xxxxxxxxx> > > > > > > > Cc: Ben Widawsky <ben@xxxxxxxxxxxx> > > > > > > > > > > > > Nice catch. Should we do this in general as part of our gem_quiescent_gpu > > > > > > helper? All i-g-t testcase are written under the assumption that they > > > > > > completel own the gpu and that the gtt is completely empty besides the few > > > > > > driver-allocated and pinned objects. So trying really hard to get rid of > > > > > > any residual stuff sounds like a good idea. > > > > > > > > > > I was going to address this in the other mail thread.... in any case, I > > > > > think not. I believe a separate helper is the way to go, and we should > > > > > only call it when we absolutely want to. > > > > > > > > > > Though it's not the intention, I've seen many tests fail because of > > > > > previous state, and I don't want to miss out on those in the future. It > > > > > would also slow down the run unnecessarily further. > > > > > > > > We already do rather eregious stuff in quiescent. So I want hard numbers > > > > on your claim that it slows down stuff further - there really shouldn't be > > > > much at all to retire/evict. > > > > -Daniel > > > > > > I don't like any of those arbitrary calls to quiescent either fwiw. > > > > > > Can't I make the same demand for data BEFORE we merge the patch that it > > > doesn't slow anything down? > > > > All those "arbitrary calls to quiescent" actually fixed spurious igt > > failures. igts are written under the assumption that _nothing_ else is > > going on in gpu-land, since otherwise it's just impossible to hit some > > races. So this is matter of correctness first and speed second. > > -Daniel > > They should be called where there are "spurious" errors and have an > understanding why it's required to do. Sprinkling synchronizing code all > over the place and calling it a fix is false. It's a "workaround" at > best, but more likely dearth of time to do it properly. I can live with > either honestly. I can't live with the statement that it's the proper > thing to do. > > Very few tests we have will actually care that _nothing_ else is > running, and if they do, annotations in code via quiescent calls is a > nice way to document it. Atm a call to quiescent_gpu on an idle machine takes roughly 25us (in a loop of 100k, snb laptop). You're optimizing the wrong thing. Also, as long as everyone bitches and moans about igt tests being unstable I'm leaning _massively_ towards stable tests results. And I've really seen too many igt tests fail spuriously so that I've decided to go back to an unconditional to quiescent_gpu (it wasn't like that originally). -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