linux-kernel - Re: [patch] Performance Counters for Linux, v4

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: <7c86c4470812162334v4515563fq8f27d5b6f381108e@mail.gmail.com>
Date:	Wed, 17 Dec 2008 08:34:07 +0100
From:	"stephane eranian" <eranian@...glemail.com>
To:	"Paul Mackerras" <paulus@...ba.org>
Cc:	"Peter Zijlstra" <a.p.zijlstra@...llo.nl>,
	"Ingo Molnar" <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	"Thomas Gleixner" <tglx@...utronix.de>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Eric Dumazet" <dada1@...mosbay.com>,
	"Robert Richter" <robert.richter@....com>,
	"Arjan van de Ven" <arjan@...radead.org>,
	"Peter Anvin" <hpa@...or.com>,
	"David S. Miller" <davem@...emloft.net>,
	perfctr-devel@...ts.sourceforge.net
Subject: Re: [patch] Performance Counters for Linux, v4

Paul,

On Wed, Dec 17, 2008 at 12:06 AM, Paul Mackerras <paulus@...ba.org> wrote:
>
> I think we need a "full-time" attribute for counters and groups that
> says "I need to be on the whole time", where "whole time" means
> whenever the task is running, for a per-task counter or group, or
> continuously for per-cpu counters/groups.
>
Who would want not to be the only owner of the PMU?

Especially when you know that if you don't, you may be sharing it
with another user who may perturb your measurement, for instance
because of heavy sampling while you are just counting. It is a tradeoff
between flexibility and accuracy. Which one is more important?
--
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/