On Wed, May 23, 2012 at 12:41 PM, Dave Airlie <airlied@xxxxxxxxx> wrote: > On Wed, May 23, 2012 at 5:26 PM, Jerome Glisse <j.glisse@xxxxxxxxx> wrote: >> On Wed, May 23, 2012 at 12:08 PM, Dave Airlie <airlied@xxxxxxxxx> wrote: >>> On Wed, May 23, 2012 at 3:48 PM, Jerome Glisse <j.glisse@xxxxxxxxx> wrote: >>>> On Wed, May 23, 2012 at 8:34 AM, Christian König >>>> <deathsimple@xxxxxxxxxxx> wrote: >>>>> On 23.05.2012 11:27, Dave Airlie wrote: >>>>>> >>>>>> On Thu, May 17, 2012 at 7:28 PM,<j.glisse@xxxxxxxxx> wrote: >>>>>>> >>>>>>> So here is improved patchset, where i splited ground work necessary >>>>>>> for the dumping into their own patch. The debugfs improvement could >>>>>>> probably be usefull to intel instead of having i915 have it's own >>>>>>> debugfs file stuff. >>>>>>> >>>>>>> The lockup dumping public api have been move into radeon_drm.h >>>>>>> >>>>>>> Stressing the fact again that dump are self contained ie they have >>>>>>> all the data needed to be replayed (vertex, indices, shader, texture, >>>>>>> ...). >>>>>>> >>>>>>> Would really like to get this into 3.5, the new API is pretty much >>>>>>> straightforward and userspace tools can easily be made to convert >>>>>>> it to other format. The change to the driver is self contained. >>>>>> >>>>>> I really don't like introducing this at this stage into 3.5, >>>>>> >>>>>> I'd really like a good review of the API and what information we provide >>>>>> along with how extensible it is. >>>>>> >>>>>> I'm still not convinced replay is what we want in the field, I know its >>>>>> what >>>>>> *you* want, but I think apitrace stuff in userspace pretty much covers >>>>>> the replaying situation. So I'd have to look at this and see how easy >>>>>> it makes disecting command streams etc. >>>>>> >>>>>> Dave. >>>>> >>>>> >>>>> I agree that it might not be a good idea to push that into 3.5, since at >>>>> least I (and I also think Alex) didn't had time to look into it yet. On the >>>>> other hand the patches look quite reasonable. >>>>> >>>>> But I still wanted to throw in a requirement from my day to day work, maybe >>>>> that helps finding a more general solution: >>>>> When we start to work with more parts of the chip it might be necessary to >>>>> dump everything that is currently "in the fly". For example I had a whole >>>>> bunch of problems where copying data around with a 3D Blit and then missing >>>>> a sync between this job and a job on another rings causes a "hiccup" in the >>>>> hardware. >>>>> >>>>> I know that this isn't your focus and that is absolutely ok with me, cause >>>>> the format you are introducing is just used in debugfs and so not part of >>>>> any stable API (at least not in my understanding), but you should still keep >>>>> in mind that we might need to extend it into that direction in the future. >>>>> >>>>> Christian. >>>> >>>> Note that my format is also done with that in mind, it can capture ib >>>> from all rings. The only thing i don't think worth capturing are the >>>> ring themself because there would be no way to replay them without >>>> adding some new special API. >>> >>> I'd like to dump the rings as well, as I said I'd rather we didn't >>> limit this to replay, but make it useful for getting as much info as >>> possible out >>> >>> Dave. >> >> Ring will contains very little, like ib schedule and fence, i don't >> see how useful this can be. >> > > In case we have a bug in our ib scheduling or fencing :-0 > > Dave. Well i think we have several kind of lockup, the most basic one is userspace sending broken shader, vertex, or something in that line. The more complex one is timing related, like a bo move or some cache invalidation that didn't happen properly and GPU endup reading either wrong data or old cached data. I don't see how to capture useful information for this second case, beside doing snapshot of memory. For multi-ring i agree that dumping the ring might prove useful spot inter-ring semaphore deadlock, or possibly inter-ring absence of synchronization (but that would be a bad kernel bug). Cheers, Jerome _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
