Re: [2.6.16-mm1 patch] throttling tree patches
- From: Mike Galbraith <efault@xxxxxx>
- Date: Sat, 25 Mar 2006 06:11:59 +0100
On Sat, 2006-03-25 at 11:37 +1100, Peter Williams wrote:
Mike Galbraith wrote:
Greetings,
I've broken down my throttling tree into 6 patches, which I'll send as
replies to this start-point.
Patch 1/6
Ignore timewarps caused by SMP timestamp rounding. Also, don't stamp a
task with a computed timestamp, stamp with the already called clock.
Signed-off-by: Mike Galbraith <efault@xxxxxx>
--- linux-2.6.16-mm1/kernel/sched.c.org 2006-03-23 15:01:41.000000000 +0100
+++ linux-2.6.16-mm1/kernel/sched.c 2006-03-23 15:02:25.000000000 +0100
@@ -805,6 +805,16 @@
unsigned long long __sleep_time = now - p->timestamp;
unsigned long sleep_time;
+ /*
+ * On SMP systems, a task can go to sleep on one CPU and
+ * wake up on another. When this happens, the timestamp
+ * is rounded to the nearest tick,
Is this true? There's no rounding that I can see.
Instrumenting it looked the same as rounding down, putting now in the
past was the result.
Of course, that doesn't mean that this chunk of code isn't required just
that the comment is misleading.
I'm not attached to the comment.
-Mike
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- [2.6.16-mm1 patch] throttling tree patches
- From: Mike Galbraith
- Re: [2.6.16-mm1 patch] throttling tree patches
- From: Peter Williams
- [2.6.16-mm1 patch] throttling tree patches
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