I see a few cleanups on Patch #3 which actually belong in patch #1: > +void drm_sched_stop(struct drm_gpu_scheduler *sched, struct > drm_sched_job *bad) The "bad" job parameter actually isn't used any more, isn't it? > +retry_wait: Not used any more. But apart from that at least patch #1 and #2 look like they can have my rb now. Patch #3 looks also like it should work after a bit of polishing. Thanks, Christian. Am 18.01.19 um 20:15 schrieb Grodzovsky, Andrey: > Attached series is the first 2 patches we already discussed about ring > mirror list handling racing with all your comments fixed (still not > committed). The third patch is a prototype based on the first 2 patches > and on our discussion. > > Please take a look. > > Andrey > > > On 01/18/2019 01:32 PM, Koenig, Christian wrote: >> Am 18.01.19 um 18:34 schrieb Grodzovsky, Andrey: >>> On 01/18/2019 12:10 PM, Koenig, Christian wrote: >>>> Am 18.01.19 um 16:21 schrieb Grodzovsky, Andrey: >>>>> On 01/18/2019 04:25 AM, Koenig, Christian wrote: >>>>>> [SNIP] >>>>>>>>>> Re-arming the timeout should probably have a much reduced value >>>>>>>>>> when the job hasn't changed. E.g. something like a few ms. >>>>>>> Now i got thinking about non hanged job in progress (job A) and let's >>>>>>> say it's a long job , it just started executing but due to time out of >>>>>>> another job (job B) on another (or this scheduler) it's parent cb got >>>>>>> disconnected, we disarmed the tdr timer for the job's scheduler, >>>>>>> meanwhile the timed out job did manage to complete before HW reset >>>>>>> check and hence we skip HW reset, attach back the cb and rearm job's A >>>>>>> tdr timer with a future value of few ms only - aren't we going to get >>>>>>> false tdr triggered on job B now because we didn't let it enough time >>>>>>> to run and complete ? I would prefer the other extreme of longer time >>>>>>> for time out to trigger then false TDR. Optimally we would have per >>>>>>> job timer and rearm to exactly the reminder of it's time out value - >>>>>>> but we gave up on per job tdr work long ago. >>>>>> Well we only re-arm the timeout with a shorter period if it already >>>>>> triggered once. If we just suspend the timeout then we should still use >>>>>> the longer period. >>>>> Can you explain more on this ? I don't get it. >>>> See drm_sched_job_timedout(), we re-arm the timeout at the end of the >>>> procedure. >>>> >>>> We should change that and re-arm the timer with a much lower timeout if >>>> the job is still not finished. >>>> >>>> Christian. >>> I still don't see how this can fix the problem of of long job in >>> progress triggering false tdr if no HW reset was done, but maybe I am >>> missing other pieces you have in mind, I will finish the patch and send >>> it and then we can be more specific based on the code. >> Ok sounds good. We should probably discuss less on details and prototype >> a bit more. >> >> Might be that I'm missing something here as well, so probably good to >> have some code to talk about things more directly. >> >> Christian. >> >>> Andrey >>> >>>>> Andrey >>>>> >>>>>>> In general the more i think about it (correct me if I am wrong) I am >>>>>>> less sure how much the optimization feature is useful - if job's time >>>>>>> out did trigger what are the chances that the little more time we give >>>>>>> it between beginning of tdr function and the time we do start the >>>>>>> actual HW reset will be exactly what it needed to complete. Also, this >>>>>>> is still not water proof as the job might complete and signal it's HW >>>>>>> fence exactly after we checked for completion but before starting the >>>>>>> HW reset code. >>>>>> I don't see this as an optimization, but rather as mandatory for correct >>>>>> operation. >>>>>> >>>>>> See without this we can run into issues because we execute jobs multiple >>>>>> times. That can still happen with this clean handling, but it is much >>>>>> more unlikely. >>>>>> >>>>>> Christian. >>>>>> >>>>>>> Andrey >>>>>>> >>>>>>>>> By unchanged you mean when we didn't resubmit the job because of the >>>>>>>>> optimized non HW reset, right ? >>>>>>>> Correct, yes. >>>>>>>> >>>>>>>>>>> About flushing tdr jobs in progress from .free_job cb - looks like >>>>>>>>>>> drm_sched_job_finish->cancel_delayed_work_sync is not enough, we >>>>>>>>>>> still need to take care of flushing all sced->work_tdr for a >>>>>>>>>>> device and for all devices in hive for XGMI. >>>>>>>>>>> What do you think ? >>>>>>>>>> Why should that be necessary? We only wait for the delayed work to >>>>>>>>>> make sure that the job is not destroyed while dealing with it. >>>>>>>>>> >>>>>>>>>> Christian. >>>>>>>>> But we might not be waiting for the correct sched->work_tdr, we do >>>>>>>>> the reset routine for all schedulers in a device accessing their >>>>>>>>> jobs too and not only for the scheduler to which the job belongs. >>>>>>>>> For XGMI not only that, we reset all the devices in the hive. >>>>>>>> That is harmless you only need to wait for the work_tdr of the >>>>>>>> current scheduler, not for all of them. >>>>>>>> >>>>>>>>> I was thinking, amdgpu driver is not even interested in allowing >>>>>>>>> multiple sced->tdr to execute together - we have to serialize all of >>>>>>>>> them anyway with the trylock mutex (even without XGMI), v3d in >>>>>>>>> v3d_job_timedout seems also to reset all of his schedulers from the >>>>>>>>> tdr work. Would it make sense to provide the sched->work_td as init >>>>>>>>> parameter to scheduler (same one for all schedulers) so we can >>>>>>>>> enforce serialization by disallowing more then 1 tdr work to execute >>>>>>>>> in the same time ? Other drivers interested to do in parallel can >>>>>>>>> provide unique sched->work_tdr per scheduler. This does imply >>>>>>>>> drm_sched_job_timedout has to removed and delegated to specific >>>>>>>>> driver implementation as probably other code dealing with >>>>>>>>> sched->work_tdr... Maybe even move tdr handling to the driver all >>>>>>>>> together ? >>>>>>>> Yeah, I was thinking something similar. The problem with this >>>>>>>> approach is that a delayed work item can have only one delay, but for >>>>>>>> multiple engines we need multiple delays. >>>>>>>> >>>>>>>> What we could do is to make it a timer instead and raise the work >>>>>>>> item from the device specific callback. >>>>>>>> >>>>>>>> But that doesn't really saves us the stop all schedulers trouble, so >>>>>>>> it doesn't buy us much in the end if I see this correctly. >>>>>>>> >>>>>>>> Christian. >>>>>> _______________________________________________ >>>>>> amd-gfx mailing list >>>>>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx >>>>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
