On Mon, 2011-03-07 at 18:18 +0000, Maarten Maathuis wrote: > On Fri, Mar 4, 2011 at 4:49 PM, Marcin Slusarz <[email protected]> > wrote: > > On Sun, Feb 13, 2011 at 09:38:04PM +0100, Marcin Slusarz wrote: > >> Combination of locking and interchannel synchronization changes > >> uncovered poor behaviour of nouveau_fence_wait, which on HZ=100 > >> configuration could waste up to 10 ms per call. > >> Depending on application, it lead to 10-30% FPS regression. > >> To fix it, shorten thread sleep time to 0.1 ms and ensure > >> spinning happens for at least one *full* tick. > >> > >> Signed-off-by: Marcin Slusarz <[email protected]> > >> --- > >> drivers/gpu/drm/nouveau/nouveau_fence.c | 10 ++++++++-- > >> 1 files changed, 8 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c > >> b/drivers/gpu/drm/nouveau/nouveau_fence.c > >> index 221b846..75ba5e2 100644 > >> --- a/drivers/gpu/drm/nouveau/nouveau_fence.c > >> +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c > >> @@ -27,6 +27,9 @@ > >> #include "drmP.h" > >> #include "drm.h" > >> > >> +#include <linux/ktime.h> > >> +#include <linux/hrtimer.h> > >> + > >> #include "nouveau_drv.h" > >> #include "nouveau_ramht.h" > >> #include "nouveau_dma.h" > >> @@ -230,9 +233,12 @@ int > >> __nouveau_fence_wait(void *sync_obj, void *sync_arg, bool lazy, bool intr) > >> { > >> unsigned long timeout = jiffies + (3 * DRM_HZ); > >> - unsigned long sleep_time = jiffies + 1; > >> + unsigned long sleep_time = jiffies + 2; > >> + ktime_t t; > >> int ret = 0; > >> > >> + t = ktime_set(0, NSEC_PER_MSEC / 10); > >> + > >> while (1) { > >> if (__nouveau_fence_signalled(sync_obj, sync_arg)) > >> break; > >> @@ -245,7 +251,7 @@ __nouveau_fence_wait(void *sync_obj, void *sync_arg, > >> bool lazy, bool intr) > >> __set_current_state(intr ? TASK_INTERRUPTIBLE > >> : TASK_UNINTERRUPTIBLE); > >> if (lazy && time_after_eq(jiffies, sleep_time)) > >> - schedule_timeout(1); > >> + schedule_hrtimeout(&t, HRTIMER_MODE_REL); > >> > >> if (intr && signal_pending(current)) { > >> ret = -ERESTARTSYS; > >> -- > >> 1.7.4.rc3 > >> > > > > ping again > > _______________________________________________ > > Nouveau mailing list > > [email protected] > > http://lists.freedesktop.org/mailman/listinfo/nouveau > > > > This looks ok to me, but I would like to get Ben Skeggs ok on this one > as well. So i've CC'ed him, hopefully he'll notice :-) Ah sorry, I have actually looked at this quite a while back but came to no solid conclusion.
While yes, I did see some minor performance improvement from it, I also notice that now we once again get 100% CPU usage while an app is waiting for the GPU a lot.. Ben. > _______________________________________________ Nouveau mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/nouveau
