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From: William Lee Irwin III <wli@holomorphy.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: Andy Whitcroft <apw@shadowen.org>,
	Martin Bligh <mbligh@google.com>,
	Dave Hansen <hansendc@us.ibm.com>, Andi Kleen <ak@suse.de>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-mm@kvack.org,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 1/4] x86_64: (SPARSE_VIRTUAL doubles sparsemem speed)
Date: Mon, 9 Apr 2007 09:40:29 -0700	[thread overview]
Message-ID: <20070409164029.GT2986@holomorphy.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0704071455060.31468@schroedinger.engr.sgi.com>

On Sat, Apr 07, 2007 at 03:06:13PM -0700, Christoph Lameter wrote:
> +/*
> + * Performance Counters and Measurement macros
> + * (C) 2005 Silicon Graphics Incorporated
> + * by Christoph Lameter <clameter@sgi.com>, April 2005
> + *
> + * Counters are calculated using the cycle counter. If a process
> + * is migrated to another cpu during the measurement then the measurement
> + * is invalid.
> + *
> + * We cannot disable preemption during measurement since that may interfere
> + * with other things in the kernel and limit the usefulness of the counters.
> + */

Whatever's going on with the rest of this, I really like this
instrumentation patch. It may be worthwhile to allow pc_start() to be
overridden so things like performance counter MSR's are usable, but
the framework looks very useful.


-- wli

WARNING: multiple messages have this Message-ID (diff)
From: William Lee Irwin III <wli@holomorphy.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: Andy Whitcroft <apw@shadowen.org>,
	Martin Bligh <mbligh@google.com>,
	Dave Hansen <hansendc@us.ibm.com>, Andi Kleen <ak@suse.de>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-mm@kvack.org,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 1/4] x86_64: (SPARSE_VIRTUAL doubles sparsemem speed)
Date: Mon, 9 Apr 2007 09:40:29 -0700	[thread overview]
Message-ID: <20070409164029.GT2986@holomorphy.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0704071455060.31468@schroedinger.engr.sgi.com>

On Sat, Apr 07, 2007 at 03:06:13PM -0700, Christoph Lameter wrote:
> +/*
> + * Performance Counters and Measurement macros
> + * (C) 2005 Silicon Graphics Incorporated
> + * by Christoph Lameter <clameter@sgi.com>, April 2005
> + *
> + * Counters are calculated using the cycle counter. If a process
> + * is migrated to another cpu during the measurement then the measurement
> + * is invalid.
> + *
> + * We cannot disable preemption during measurement since that may interfere
> + * with other things in the kernel and limit the usefulness of the counters.
> + */

Whatever's going on with the rest of this, I really like this
instrumentation patch. It may be worthwhile to allow pc_start() to be
overridden so things like performance counter MSR's are usable, but
the framework looks very useful.


-- wli

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  parent reply	other threads:[~2007-04-09 17:06 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-01  7:10 [PATCH 1/2] Generic Virtual Memmap suport for SPARSEMEM Christoph Lameter
2007-04-01  7:10 ` Christoph Lameter
2007-04-01  7:10 ` [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL Christoph Lameter
2007-04-01  7:10   ` Christoph Lameter
2007-04-01  7:11   ` Christoph Lameter
2007-04-01  7:11     ` Christoph Lameter
2007-04-01 10:46   ` Andi Kleen
2007-04-01 10:46     ` Andi Kleen
2007-04-02 15:37     ` Christoph Lameter
2007-04-02 15:37       ` Christoph Lameter
2007-04-02 15:44       ` Andi Kleen
2007-04-02 15:44         ` Andi Kleen
2007-04-02 15:51         ` Martin J. Bligh
2007-04-02 15:51           ` Martin J. Bligh
2007-04-02 15:54         ` Christoph Lameter
2007-04-02 15:54           ` Christoph Lameter
2007-04-02 17:14           ` Andi Kleen
2007-04-02 17:14             ` Andi Kleen
2007-04-02 17:34             ` Christoph Lameter
2007-04-02 17:34               ` Christoph Lameter
2007-04-02 19:54           ` Dave Hansen
2007-04-02 19:54             ` Dave Hansen
2007-04-02 20:11             ` Christoph Lameter
2007-04-02 20:11               ` Christoph Lameter
2007-04-02 20:13       ` Dave Hansen
2007-04-02 20:13         ` Dave Hansen
2007-04-02 20:30         ` Christoph Lameter
2007-04-02 20:30           ` Christoph Lameter
2007-04-02 20:38           ` Martin Bligh
2007-04-02 20:38             ` Martin Bligh
2007-04-02 20:51             ` Christoph Lameter
2007-04-02 20:51               ` Christoph Lameter
2007-04-05 11:50               ` Andy Whitcroft
2007-04-05 11:50                 ` Andy Whitcroft
2007-04-05 18:27                 ` Christoph Lameter
2007-04-05 18:27                   ` Christoph Lameter
2007-04-07 22:06                   ` [PATCH 1/4] x86_64: (SPARSE_VIRTUAL doubles sparsemem speed) Christoph Lameter
2007-04-07 22:06                     ` Christoph Lameter
2007-04-07 22:18                     ` Andi Kleen
2007-04-07 22:18                       ` Andi Kleen
2007-04-09 16:40                     ` William Lee Irwin III [this message]
2007-04-09 16:40                       ` William Lee Irwin III
2007-04-09 17:16                       ` Christoph Lameter
2007-04-09 17:16                         ` Christoph Lameter
2007-04-09 18:20                         ` William Lee Irwin III
2007-04-09 18:20                           ` William Lee Irwin III
2007-04-02 21:08           ` [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL Dave Hansen
2007-04-02 21:08             ` Dave Hansen
2007-04-02 21:28             ` Christoph Lameter
2007-04-02 21:28               ` Christoph Lameter
2007-04-02 21:43               ` Martin Bligh
2007-04-02 21:43                 ` Martin Bligh
2007-04-02 21:56               ` Dave Hansen
2007-04-02 21:56                 ` Dave Hansen
2007-04-02 22:29                 ` Christoph Lameter
2007-04-02 22:29                   ` Christoph Lameter
2007-04-02 22:31                 ` Andi Kleen
2007-04-02 22:31                   ` Andi Kleen
2007-04-02 22:37                   ` Christoph Lameter
2007-04-02 22:37                     ` Christoph Lameter
2007-04-02 22:41                     ` Martin Bligh
2007-04-02 22:41                       ` Martin Bligh
2007-04-02 22:49                       ` Christoph Lameter
2007-04-02 22:49                         ` Christoph Lameter
2007-04-02 22:52                         ` Martin Bligh
2007-04-02 22:52                           ` Martin Bligh
2007-04-05 12:07                   ` Andy Whitcroft
2007-04-05 12:07                     ` Andy Whitcroft
2007-04-04 21:27               ` Bob Picco
2007-04-04 21:27                 ` Bob Picco
2007-04-04 22:38                 ` Christoph Lameter
2007-04-04 22:38                   ` Christoph Lameter
2007-04-02 23:03       ` Bjorn Helgaas
2007-04-02 23:03         ` Bjorn Helgaas
2007-04-02 15:44     ` Christoph Lameter
2007-04-02 15:44       ` Christoph Lameter
2007-04-02 16:18     ` Christoph Lameter
2007-04-02 16:18       ` Christoph Lameter
2007-04-02 20:50 ` [PATCH 1/2] Generic Virtual Memmap suport for SPARSEMEM Dave Hansen
2007-04-02 20:50   ` Dave Hansen
2007-04-02 21:00   ` Christoph Lameter
2007-04-02 21:00     ` Christoph Lameter
2007-04-02 21:22     ` Dave Hansen
2007-04-02 21:22       ` Dave Hansen
2007-04-02 21:31       ` Christoph Lameter
2007-04-02 21:31         ` Christoph Lameter
2007-04-02 21:42         ` Dave Hansen
2007-04-02 21:42           ` Dave Hansen
2007-04-02 21:53           ` Christoph Lameter
2007-04-02 21:53             ` Christoph Lameter
2007-04-02 22:05             ` Dave Hansen
2007-04-02 22:05               ` Dave Hansen

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