drm/nouveau: fix __nouveau_fence_wait performance
Commit 21e86c1c8a844bf978f8fc431a59c9f5a578812d ("drm/nouveau: remove
cpu_writers lock") turned on lazy waits. Unfortunately
__nouveau_fence_wait was not optimized for this case and on HZ=100
kernel wasted up to 10 ms per call.
Depending on application, it led to 10-30% FPS regression.
Fix it.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c
index a244702..4b9f449 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"
@@ -229,7 +232,8 @@
__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 = NSEC_PER_MSEC / 1000;
+ ktime_t t;
int ret = 0;
while (1) {
@@ -243,8 +247,13 @@
__set_current_state(intr ? TASK_INTERRUPTIBLE
: TASK_UNINTERRUPTIBLE);
- if (lazy && time_after_eq(jiffies, sleep_time))
- schedule_timeout(1);
+ if (lazy) {
+ t = ktime_set(0, sleep_time);
+ schedule_hrtimeout(&t, HRTIMER_MODE_REL);
+ sleep_time *= 2;
+ if (sleep_time > NSEC_PER_MSEC)
+ sleep_time = NSEC_PER_MSEC;
+ }
if (intr && signal_pending(current)) {
ret = -ERESTARTSYS;