From: Andi Kleen <andi@firstfloor.org>
To: Stephane Eranian <eranian@hpl.hp.com>
Cc: Andi Kleen <andi@firstfloor.org>,
akpm@osdl.org, Robert Richter <robert.richter@amd.com>,
gregkh@suse.de, linux-kernel@vger.kernel.org,
perfmon@napali.hpl.hp.com, William Cohen <wcohen@redhat.com>,
perfmon2-devel@lists.sourceforge.net
Subject: Re: [perfmon] Re: [perfmon2] perfmon2 merge news
Date: Tue, 13 Nov 2007 23:25:34 +0100 [thread overview]
Message-ID: <20071113222534.GC17145@one.firstfloor.org> (raw)
In-Reply-To: <20071113222234.GH5747@frankl.hpl.hp.com>
On Tue, Nov 13, 2007 at 02:22:34PM -0800, Stephane Eranian wrote:
> Andi,
> On Tue, Nov 13, 2007 at 10:50:56PM +0100, Andi Kleen wrote:
> > > Yes, horribly more complicated because of locking issues within perfmon.
> > > As soon as you expose a file descriptor, you need some locking to prevent
> > > multiple user threads (malicious or not) to compete to access the PMU state.
> >
> > Why do you need the file descriptor?
> >
>
> To identify your monitoring session be it system-wide (i.e., per-cpu) or per-thread.
> file descriptor allows you to use close, read, select, poll and you leverage the
Surely that could be done with a flag for each call too? Keeping file descriptors
to pass essentially a boolean seems overkill.
> existing file descriptor sharing/inheritance sematics. At the kernel level, a
> descriptor provides all the callback necessary to make sure you clean up the perfmon
> session state on exit.
Didn't you already have a thread destructor for it?
-Andi
next prev parent reply other threads:[~2007-11-13 22:25 UTC|newest]
Thread overview: 116+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-07 0:34 [PATCH] fix up perfmon to build on -mm Greg KH
2007-11-07 10:34 ` Stephane Eranian
2007-11-07 17:07 ` Greg KH
2007-11-07 13:42 ` Stephane Eranian
2007-11-07 17:08 ` Greg KH
2007-11-07 17:33 ` Andrew Morton
2007-11-07 17:41 ` Greg KH
2007-11-07 17:50 ` Stephane Eranian
2007-11-07 17:47 ` Greg KH
2007-11-07 17:57 ` Stephane Eranian
2007-11-07 19:53 ` Greg KH
2007-11-07 20:39 ` Stephane Eranian
2007-11-08 15:27 ` Stephane Eranian
2007-11-09 20:06 ` Andrew Morton
2007-11-09 21:38 ` Greg KH
2007-11-10 20:32 ` Andi Kleen
2007-11-13 15:17 ` perfmon2 merge news Robert Richter
2007-11-13 15:35 ` [perfmon2] " William Cohen
2007-11-13 17:55 ` Stephane Eranian
2007-11-13 18:33 ` [perfmon] " William Cohen
2007-11-13 21:13 ` Stephane Eranian
2007-11-13 21:29 ` Andi Kleen
2007-11-13 21:46 ` Stephane Eranian
2007-11-13 21:50 ` Andi Kleen
2007-11-13 22:22 ` Stephane Eranian
2007-11-13 22:25 ` Andi Kleen [this message]
2007-11-13 22:58 ` Stephane Eranian
2007-11-14 2:07 ` Andi Kleen
2007-11-14 13:09 ` Stephane Eranian
2007-11-14 14:24 ` Andi Kleen
2007-11-14 15:44 ` William Cohen
2007-11-14 16:13 ` Stephane Eranian
2007-11-14 18:53 ` Philippe Elie
2007-11-14 19:15 ` Andi Kleen
2007-11-15 0:07 ` Stephane Eranian
2007-11-13 18:47 ` Philip Mucci
2007-11-13 18:59 ` Greg KH
2007-11-13 20:07 ` Andrew Morton
2007-11-13 20:14 ` Greg KH
2007-11-13 20:36 ` Andi Kleen
2007-11-14 0:28 ` Philip Mucci
2007-11-14 1:52 ` Andi Kleen
2007-11-16 9:18 ` Philip Mucci
2007-11-16 15:15 ` Andi Kleen
2007-11-16 16:00 ` Stephane Eranian
2007-11-16 16:28 ` Andi Kleen
2007-11-16 17:13 ` William Cohen
2007-11-16 21:56 ` Stephane Eranian
2007-11-16 17:36 ` Stephane Eranian
2007-11-16 17:51 ` dean gaudet
2007-11-17 0:29 ` David Miller
2007-11-17 1:07 ` Greg KH
2007-11-16 20:16 ` Philip Mucci
2007-11-17 0:15 ` David Miller
[not found] ` <1d7226b10711161713j675341b7wdb4f050c59a8be0a@mail.gmail.com>
2007-11-17 1:25 ` Greg KH
[not found] ` <1d7226b10711161748n39b7f195q796d85282ef66134@mail.gmail.com>
2007-11-17 2:13 ` Greg KH
2007-11-14 7:24 ` [perfmon] Re: [perfmon2] " Paul Mackerras
2007-11-14 7:40 ` Andrew Morton
2007-11-14 10:38 ` Christoph Hellwig
2007-11-14 10:43 ` Paul Mackerras
2007-11-14 11:00 ` Christoph Hellwig
2007-11-14 11:12 ` David Miller
2007-11-14 11:14 ` David Miller
2007-11-14 11:44 ` Paul Mackerras
2007-11-13 23:49 ` Nick Piggin
2007-11-14 11:58 ` David Miller
2007-11-14 0:25 ` Nick Piggin
2007-11-14 21:30 ` Paul Mackerras
2007-11-14 10:17 ` Nick Piggin
2007-11-14 22:56 ` Chuck Ebbert
2007-11-14 11:03 ` Nick Piggin
2007-11-14 11:52 ` David Miller
2007-11-14 12:03 ` Paul Mackerras
2007-11-14 12:07 ` David Miller
2007-11-14 0:28 ` Nick Piggin
2007-11-14 21:50 ` Paul Mackerras
2007-11-14 23:03 ` David Miller
2007-11-14 23:12 ` Paul Mackerras
2007-11-14 23:21 ` David Miller
2007-11-15 1:11 ` Paul Mackerras
2007-11-15 1:27 ` David Miller
2007-11-15 2:34 ` Paul Mackerras
2007-11-15 7:48 ` Herbert Xu
2007-11-15 8:19 ` Andi Kleen
2007-11-19 13:08 ` David Miller
2007-11-19 20:53 ` Stephane Eranian
2007-11-20 0:55 ` David Miller
2007-11-19 21:43 ` Paul Mackerras
2007-11-19 22:48 ` Stephane Eranian
2007-11-20 0:53 ` David Miller
2007-12-13 16:00 ` Stephane Eranian
2007-12-14 19:12 ` Frank Ch. Eigler
2007-12-14 21:07 ` Stephane Eranian
2007-12-15 15:54 ` Frank Ch. Eigler
2007-11-15 8:29 ` [perfmon] " Stephane Eranian
2007-11-14 13:51 ` Stephane Eranian
2007-11-14 11:39 ` Paul Mackerras
2007-11-14 11:52 ` David Miller
2007-11-14 13:47 ` Stephane Eranian
2007-11-14 12:38 ` Andi Kleen
2007-11-14 14:13 ` Stephane Eranian
2007-11-14 14:26 ` Andi Kleen
2007-11-15 0:23 ` Paul Mackerras
2007-11-14 19:48 ` David Miller
2007-11-15 4:20 ` dean gaudet
2007-11-15 4:47 ` Paul Mackerras
2007-11-15 5:14 ` dean gaudet
2007-11-15 8:53 ` Stephane Eranian
2007-11-15 17:01 ` [perfmon2] [perfmon] " Dan Terpstra
2007-11-13 21:33 ` [perfmon] Re: [perfmon2] " Stephane Eranian
2007-11-13 21:45 ` Greg KH
2007-11-13 22:27 ` Christoph Hellwig
2007-11-13 20:42 ` Andi Kleen
2007-11-13 18:32 ` Stephane Eranian
2007-11-13 22:29 ` Christoph Hellwig
2007-11-16 18:25 ` PMC core internal API design Mathieu Desnoyers
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