[PATCH 04/14] smartsched: Tweak the default scheduler intervals
Adam Jackson
ajax at redhat.com
Thu Nov 21 14:43:17 PST 2013
A default timeslice of 20ms means a pathological client can ruin up to
two frames per scheduler tick. And a fifth of a second is just insane.
Pick two different numbers out of the hat. A 5ms slice means you can
probably keep up with two or three abusive clients, and letting it burst
to 15ms should give you about all the timeslice you need for a
fullscreen game (that's doing server-side rendering for some reason).
If you're running on a system with a 10ms granularity on SIGALRM, then
this effectively changes the intervals to 10ms and 30ms. Which is still
better, just not as better.
I suspect this is about as good as we can do without actually going
preemptive, which is an entire other nightmare.
Signed-off-by: Adam Jackson <ajax at redhat.com>
---
dix/dispatch.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/dix/dispatch.c b/dix/dispatch.c
index 4fecfea..8dcd9cb 100644
--- a/dix/dispatch.c
+++ b/dix/dispatch.c
@@ -220,8 +220,9 @@ UpdateCurrentTimeIf(void)
#undef SMART_DEBUG
-#define SMART_SCHEDULE_DEFAULT_INTERVAL 20 /* ms */
-#define SMART_SCHEDULE_MAX_SLICE 200 /* ms */
+/* in milliseconds */
+#define SMART_SCHEDULE_DEFAULT_INTERVAL 5
+#define SMART_SCHEDULE_MAX_SLICE 15
#if defined(WIN32) && !defined(__CYGWIN__)
Bool SmartScheduleDisable = TRUE;
--
1.8.4.2
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