From: Ingo Molnar <mingo@elte.hu>
To: Gleb Natapov <gleb@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>, Avi Kivity <avi@redhat.com>,
Robert Richter <robert.richter@amd.com>,
Benjamin Block <bebl@mageta.org>,
Hans Rosenfeld <hans.rosenfeld@amd.com>,
hpa@zytor.com, tglx@linutronix.de, suresh.b.siddha@intel.com,
eranian@google.com, brgerst@gmail.com, Andreas.Herrmann3@amd.com,
x86@kernel.org, linux-kernel@vger.kernel.org,
Benjamin Block <benjamin.block@amd.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC 4/5] x86, perf: implements lwp-perf-integration (rc1)
Date: Fri, 23 Dec 2011 11:56:08 +0100 [thread overview]
Message-ID: <20111223105608.GH4749@elte.hu> (raw)
In-Reply-To: <20111221114601.GA2446@redhat.com>
* Gleb Natapov <gleb@redhat.com> wrote:
> On Tue, Dec 20, 2011 at 07:40:04PM +0100, Ingo Molnar wrote:
> > > The point is, if user-space re-programs LWP it will continue
> > > to write its samples to the new ring-buffer virtual-address
> > > set up by user-space. It will still use that virtual address
> > > in another address-space after a task-switch. This allows
> > > processes to corrupt memory of other processes. [...]
> >
> > That's nonsense. As i said it my previous mail the LWPC
> > should be per task and switched on task switch - just like
> > the DS/PEBS context is.
>
> Is it? Looking at arch/x86/kernel/cpu/perf_event_intel_ds.c it
> seems like DS is per cpu, not per task.
We flush it on context switch and reuse it for the next task via
the x86_pmu.drain_pebs() callback - so the buffering of PEBS
events is per task.
Thanks,
Ingo
next prev parent reply other threads:[~2011-12-23 10:58 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-29 12:41 [PATCH 0/9] rework of extended state handling, LWP support Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 1/9] x86, xsave: warn on #NM exceptions caused by the kernel Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 2/9] x86, xsave: cleanup fpu/xsave support Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 3/9] x86, xsave: cleanup fpu/xsave signal frame setup Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 4/9] x86, xsave: rework fpu/xsave support Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 5/9] x86, xsave: remove unused code Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 6/9] x86, xsave: more cleanups Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 7/9] x86, xsave: remove lazy allocation of xstate area Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 8/9] x86, xsave: add support for non-lazy xstates Hans Rosenfeld
2011-11-29 12:41 ` [PATCH 9/9] x86, xsave: add kernel support for AMDs Lightweight Profiling (LWP) Hans Rosenfeld
2011-11-29 21:31 ` [PATCH 0/9] rework of extended state handling, LWP support Andi Kleen
2011-11-30 17:37 ` Hans Rosenfeld
2011-11-30 21:52 ` Andi Kleen
2011-12-01 20:36 ` Hans Rosenfeld
2011-12-02 2:01 ` H. Peter Anvin
2011-12-02 11:20 ` Hans Rosenfeld
2011-12-07 19:57 ` Hans Rosenfeld
2011-12-07 20:00 ` [PATCH 7/8] x86, xsave: add support for non-lazy xstates Hans Rosenfeld
2011-12-07 20:00 ` [PATCH 8/8] x86, xsave: add kernel support for AMDs Lightweight Profiling (LWP) Hans Rosenfeld
2011-12-05 10:22 ` [PATCH 0/9] rework of extended state handling, LWP support Ingo Molnar
2011-12-16 16:07 ` Hans Rosenfeld
2011-12-16 16:12 ` [RFC 1/5] x86, perf: Implement software-activation of lwp Hans Rosenfeld
2011-12-16 16:12 ` [RFC 2/5] perf: adds prototype for a new perf-context-type Hans Rosenfeld
2011-12-16 16:12 ` [RFC 3/5] perf: adds a new pmu-initialization-call Hans Rosenfeld
2011-12-16 16:12 ` [RFC 4/5] x86, perf: implements lwp-perf-integration (rc1) Hans Rosenfeld
2011-12-18 8:04 ` Ingo Molnar
2011-12-18 15:22 ` Benjamin Block
2011-12-18 23:43 ` Ingo Molnar
2011-12-19 9:09 ` Robert Richter
2011-12-19 10:54 ` Ingo Molnar
2011-12-19 11:12 ` Avi Kivity
2011-12-19 11:40 ` Ingo Molnar
2011-12-19 11:58 ` Avi Kivity
2011-12-19 18:13 ` Benjamin
2011-12-20 8:56 ` Ingo Molnar
2011-12-20 9:15 ` Ingo Molnar
2011-12-20 9:47 ` Avi Kivity
2011-12-20 10:09 ` Ingo Molnar
2011-12-20 15:27 ` Joerg Roedel
2011-12-20 18:40 ` Ingo Molnar
2011-12-21 0:07 ` Joerg Roedel
2011-12-21 12:34 ` Ingo Molnar
2011-12-21 12:44 ` Avi Kivity
2011-12-21 13:22 ` Ingo Molnar
2011-12-21 22:49 ` Joerg Roedel
2011-12-23 10:53 ` Ingo Molnar
2011-12-21 11:46 ` Gleb Natapov
2011-12-23 10:56 ` Ingo Molnar [this message]
2011-12-20 15:48 ` Vince Weaver
2011-12-20 18:27 ` Ingo Molnar
2011-12-20 22:47 ` Vince Weaver
2011-12-21 12:00 ` Ingo Molnar
2011-12-21 13:55 ` Vince Weaver
2011-12-16 16:12 ` [RFC 5/5] x86, perf: adds support for the LWP threshold-int Hans Rosenfeld
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