linux-kernel - Re: [PATCH] perf: Update event buffer tail when overwriting old events

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

Message-ID: <20130710114408.GS25631@dyad.programming.kicks-ass.net>
Date:	Wed, 10 Jul 2013 13:44:08 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Yan, Zheng" <zheng.z.yan@...el.com>
Cc:	linux-kernel@...r.kernel.org, mingo@...e.hu, eranian@...gle.com,
	ak@...ux.intel.com
Subject: Re: [PATCH] perf: Update event buffer tail when overwriting old
 events

On Wed, Jul 10, 2013 at 07:37:43PM +0800, Yan, Zheng wrote:
> On 07/08/2013 08:15 PM, Peter Zijlstra wrote:
> > On Thu, Jun 06, 2013 at 01:58:06PM +0800, Yan, Zheng wrote:
> >> From: "Yan, Zheng" <zheng.z.yan@...el.com>

> >>         before   overwrite mode      after   overwrite mode
> >> AVG      1000        999             1046        1044
> >> STDEV    19.4        19.5            17.1        17.9
> > 
> > OK, so I was sure I replied to this email; but apparently I didn't :/
> > 
> > So its still adding about 5% overhead to the regular case; this is sad.
> > 
> > What does something like the below do?
> > 
> 
> I re-test the patch on a different 32 core sandybridge-ep machine. the result is quite good.
> 
>        origin   origin overwrite       modified    modified overwrite
> AVG    1000      1044                   960        1006
> STDEV  39.0      26.0                   28.1       14.4

Nice! -- you did fix the snafu for the overwrite more before testing right?
--
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/