RE: A quick view of the performance benchmark for semaphore-likeand mutex

From: Chen, Dennis (SRDC SW)
Date: Tue Apr 17 2012 - 07:52:34 EST

On Tue, Apr 17, 2012 at 6:12 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Tue, 2012-04-17 at 09:36 +0000, Chen, Dennis (SRDC SW) wrote:
>> Interesting!! Semaphore-like is almost 8s slower than mutex... Also, the Events sycles of perf
>> reported is different
> I suspect that if you were to use actual semaphores it would be even
> worse, the semaphore implementation doesn't do lock-stealing nor does it
> have fancy assembly fast paths.
> In fact, I don't know why you even bother with sems, they're a
> deprecated serialization primitive that really shouldn't be used
> anymore.

Yes, I am also apt to believe that...Actually I never been bothered by sems in my real life, just
for fun! I enjoy the data :-)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at