On Thu, Oct 03, 2013 at 03:06:03AM -0500, Felipe Contreras wrote: > On Thu, Oct 3, 2013 at 2:36 AM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > > On Thu, Oct 03, 2013 at 01:29:29AM -0500, Felipe Contreras wrote: > >> It's nice to avoid X server crashes (by not passing negative values to > >> select(3)). > >> > >> For more information: > >> http://article.gmane.org/gmane.comp.freedesktop.xorg.devel/37388 > >> > >> Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx> > > > > Thanks for the patch, I pushed a slightly different version to consume > > the expired flush timeout immediately. > > > > However, in order for this to happen something within the BlockHandler > > must have run for at least 4ms. Which is itself very worrying - the two > > candidates are the throttle or lock contention. (The throttle is also > > prone to being influenced by a third party.) Such stalls are likely to > > be noticeable as jitter or judder, so if you can spot their source > > hopefully we can tackle the root cause. > > What exactly do you mean by third party? I wouldn't notice if there > was jitter because it's a loading screen, and there's absolutely no > updates on the screen; it's static. Other users of /dev/dri/card0. The most likely cause for the delay here is waiting for the GPU to complete an operation or for waiting for access to the GPU. > Do you mean you would like me to add debugging in > sna_accel_block_handler() to figure exactly which block is taking too > long to complete? Right, if you do something like: diff --git a/src/sna/sna_accel.c b/src/sna/sna_accel.c index 21cd342..31ea1a3 100644 @@ -15931,6 +15931,8 @@ void sna_accel_close(struct sna *sna) void sna_accel_block_handler(struct sna *sna, struct timeval **tv) { + uint32_t duration[NUM_TIMERS] = { 0 }; + sigtrap_assert(); if (sna->kgem.need_retire) @@ -15947,19 +15949,28 @@ void sna_accel_block_handler(struct sna *sna, struct timeval **tv) } restart: - if (sna_accel_do_flush(sna)) + if (sna_accel_do_flush(sna)) { + duration[FLUSH_TIMER] = TIME; sna_accel_flush(sna); + duration[FLUSH_TIMER] = TIME - duration[FLUSH_TIMER]; + } assert(sna_accel_scanout(sna) == NULL || sna_accel_scanout(sna)->gpu_bo->exec == NULL || sna->timer_active & (1<<(FLUSH_TIMER))); - if (sna_accel_do_throttle(sna)) + if (sna_accel_do_throttle(sna)) { + duration[THROTTLE_TIMER] = TIME; sna_accel_throttle(sna); + duration[THROTTLE_TIMER] = TIME - duration[THROTTLE_TIMER]; + } assert(!sna->kgem.need_retire || sna->timer_active & (1<<(THROTTLE_TIMER))); - if (sna_accel_do_expire(sna)) + if (sna_accel_do_expire(sna)) { + duration[EXPIRE_TIMER] = TIME; sna_accel_expire(sna); + duration[EXPIRE_TIMER] = TIME - duration[EXPIRE_TIMER]; + } assert(!sna->kgem.need_expire || sna->timer_active & (1<<(EXPIRE_TIMER))); @@ -15981,8 +15992,14 @@ restart: timeout = sna->timer_expire[FLUSH_TIMER] - TIME; DBG(("%s: flush timer expires in %d [%d]\n", __FUNCTION__, timeout, sna->timer_expire[FLUSH_TIMER])); - if (timeout < 3) + if (timeout < 3) { + ErrorF("restarting timeout[%d] (%d, %d, %d)\n", + timeout, + duration[FLUSH_TIMER], + duration[THROTTLE_TIMER], + duration[EXPIRE_TIMER]); goto restart; + } if (*tv == NULL) { *tv = &sna->timer_tv; That will hopefully catch which path is consuming too much time -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
