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From: Andrew Morton <akpm@osdl.org>
To: Mikael Pettersson <mikpe@csd.uu.se>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH][1/7] perfctr-2.7.2 for 2.6.6-mm2: core
Date: Fri, 14 May 2004 15:59:07 -0700	[thread overview]
Message-ID: <20040514155907.36246829.akpm@osdl.org> (raw)
In-Reply-To: <200405141409.i4EE9Uhd018397@alkaid.it.uu.se>

Mikael Pettersson <mikpe@csd.uu.se> wrote:
>
> - core driver files and kernel changes

Looks like we need six system calls if we're going to do it that way.

All that marshalling and unmarshalling code is a bit evil.  I wonder if
there's some way in which it can be flattened out.

One option would be to present all the info to userspace as a virtual
filesystem, although it would be a bit weird that the contents of the
"files" depends upon the process which reads them.

Maybe a mkdir() on that filesystem could create a directory which contains
files which contain the counters for the process which made the directory? 
The directory would need to be auto-rmdir'ed on process exit.  It's
basically the same semantics as /proc/pid.

But /proc/pid can be read by processes other than "pid".  Does the same
apply to the perfcntr instrumentation?  (Being able to read another
process's perfcntr info sounds useful.  Is it?)


  parent reply	other threads:[~2004-05-14 22:56 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-05-14 14:09 Mikael Pettersson
2004-05-14 14:40 ` Christoph Hellwig
2004-05-14 22:59 ` Andrew Morton [this message]
2004-05-15 14:39 Mikael Pettersson
2004-05-15 14:40 Mikael Pettersson
2004-05-16  5:39 ` Andrew Morton
2004-05-16 11:52 Mikael Pettersson

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