On Mon, 16 Jul 2012 11:51:55 -0700, Ben Widawsky <ben at bwidawsk.net> wrote: > Pros: > * Potential for per batch, or ring watchdog values. I believe when/if we > get to GPGPU workloads, this is particularly interesting. > * Batch granularity hang detection. This mostly just makes hang > detection and recovery a bit easier IMO. > > Cons: > * Blit ring doesn't have an interrupt. This means we still need the > software watchdog, and it makes hang detection more complex. I've been > led to believe future HW *may* have this interrupt. > * Semaphores Replacing the black magic for INSTDONE hang detection does seem like a sensible plan, but as long as we require the hangcheck timer we are only adding code complexity. So there really needs to a be a compelling advantage for the watchdoy, something that we cannot acheive with the existing method. For me, the criteria is whether we ever miss a hang or falsely accuse the hw of stopping. If I understand the watchdog correctly, it basically ensures the batch completes within a certain interval which we can codify into the existing hangcheck, so no USP. Or is there more magic waiting in the wings? -Chris -- Chris Wilson, Intel Open Source Technology Centre
