linux-kernel - RE: A quick view of the performance benchmark for semaphore-like and mutex

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Tue, 17 Apr 2012 11:52:26 +0000
From:	"Chen, Dennis (SRDC SW)" <Dennis1.Chen@....com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	"paulmck@...ux.vnet.ibm.com" <paulmck@...ux.vnet.ibm.com>,
	Paul Mackerras <paulus@...ba.org>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Subject: RE: A quick view of the performance benchmark for semaphore-like
 and mutex

On Tue, Apr 17, 2012 at 6:12 PM, Peter Zijlstra <peterz@...radead.org> 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@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/