Quoting Chris Wilson (2019-08-06 14:47:25) > Normally, we rely on our hangcheck to prevent persistent batches from > hogging the GPU. However, if the user disables hangcheck, this mechanism > breaks down. Despite our insistence that this is unsafe, the users are > equally insistent that they want to use endless batches and will disable > the hangcheck mechanism. We are looking are perhaps replacing hangcheck > with a softer mechanism, that sends a pulse down the engine to check if > it is well. We can use the same preemptive pulse to flush an active > persistent context off the GPU upon context close, preventing resources > being lost and unkillable requests remaining on the GPU, after process > termination. To avoid changing the ABI and accidentally breaking > existing userspace, we make the persistence of a context explicit and > enable it by default. Userspace can opt out of persistent mode (forcing > requests to be cancelled when the context is closed by process > termination or explicitly) by a context parameter, or to facilitate > existing use-cases by disabling hangcheck (i915.enable_hangcheck=0). > (Note, one of the outcomes for supporting endless mode will be the > removal of hangchecking, at which point opting into persistent mode will > be mandatory, or maybe the default.) For the record, I've finally run into examples of desktop clients exiting before their rendering is shown. No longer hypothetical. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
