[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20150226095812.GA32538@localhost>
Date: Thu, 26 Feb 2015 09:58:13 +0000
From: Catalin Marinas <catalin.marinas@....com>
To: Huang Ying <ying.huang@...el.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
LKML <linux-kernel@...r.kernel.org>, LKP ML <lkp@...org>
Subject: Re: [LKP] [futex] 76835b0ebf8: -8.1% will-it-scale.per_thread_ops
On Thu, Feb 26, 2015 at 05:16:53AM +0000, Huang Ying wrote:
> FYI, we noticed the below changes on
>
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> commit 76835b0ebf8a7fe85beb03c75121419a7dec52f0 ("futex: Ensure get_futex_key_refs() always implies a barrier")
>
>
> testbox/testcase/testparams: lkp-wsx01/will-it-scale/performance-futex4
>
> 0429fbc0bdc297d6 76835b0ebf8a7fe85beb03c751
> ---------------- --------------------------
> %stddev %change %stddev
> \ | \
> 6314259 ± 0% -8.1% 5800079 ± 0% will-it-scale.per_thread_ops
> 6274871 ± 0% -8.1% 5768747 ± 0% will-it-scale.per_process_ops
This was raised before but I'm not sure we can do much about it:
https://lkml.org/lkml/2014/10/26/189
It would be interesting to know the difference in performance with the
code prior to commits b0c29f79ecea and 11d4616bd07f which optimised the
futex code but missed a barrier.
--
Catalin
--
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/
Powered by blists - more mailing lists