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drm/nouveau: fix __nouveau_fence_wait performance

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Commit 21e86c1c8a ("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>
This commit is contained in:
Marcin Slusarz 2011-03-09 14:22:19 +01:00 committed by Ben Skeggs
parent 459ca7e528
commit bd35fe5a79
1 changed files with 12 additions and 3 deletions
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15
drivers/gpu/drm/nouveau/nouveau_fence.c
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@ -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 @@ 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 = NSEC_PER_MSEC / 1000;
ktime_t t;
int ret = 0;
while (1) {
@ -243,8 +247,13 @@ __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);
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;