linux-kernel - Re: [PATCH] perf, powerpc: Fix power_pmu_event

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 for Android: free password hash cracker in your pocket

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

Date:	Tue, 19 Oct 2010 13:50:30 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Paul Mackerras <paulus@...ba.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	linux-kernel@...r.kernel.org,
	Alexey Kardashevskiy <aik@....ibm.com>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH] perf, powerpc: Fix power_pmu_event_init to not use
 event->ctx

On Tue, 2010-10-19 at 10:28 +0200, Peter Zijlstra wrote:
 
> > (The reason it needs to know whether it is a per-task event is because
> > there are some hardware events on Power systems which only count when
> > the processor is not idle, and there are some fixed-function counters
> > which count such events.  For example, the "run cycles" event counts
> > cycles when the processor is not idle.  If the user asks to count
> > cycles, we can use "run cycles" if this is a per-task event, since the
> > processor is running when the task is running, by definition.  We
> > can't use "run cycles" if the user asks for "cycles" on a system-wide
> > counter.)

Right, so the problem comes from you using run-cycles as cycles? How
does that interact with things like cpu_relax() will that generate a
difference in run-cycles vs cycles?


--
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/