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From: "John Hawkes" <hawkes@sgi.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Tony Luck <tony.luck@gmail.com>, Andrew Morton <akpm@osdl.org>,
	linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jack Steiner <steiner@sgi.com>, Dan Higgins <djh@sgi.com>,
	Jeremy Higdon <jeremy@sgi.com>
Subject: Re: [PATCH] ia64: change usermode HZ to 250
Date: Wed, 28 Jun 2006 15:43:46 +0000	[thread overview]
Message-ID: <005e01c69ac9$a55e1bf0$6f00a8c0@comcast.net> (raw)
In-Reply-To: 1151483994.3153.5.camel@laptopd505.fenrus.org

From: "Arjan van de Ven" <arjan@infradead.org>
...
> ok why not define the userspace HZ to
>
> #define HZ sysconf(_SC_CLK_TCK)

That did occur to me.  It obviously does get the correct value.  The downside
is that one of those crufty apps that thinks it is using "HZ" as a constant
will instead be invoking a more costly syscall.  Should we care about the
resulting performance impact?

I vote for Arjan's solution.

John Hawkes


WARNING: multiple messages have this Message-ID (diff)
From: "John Hawkes" <hawkes@sgi.com>
To: "Arjan van de Ven" <arjan@infradead.org>
Cc: "Tony Luck" <tony.luck@gmail.com>,
	"Andrew Morton" <akpm@osdl.org>, <linux-ia64@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, "Jack Steiner" <steiner@sgi.com>,
	"Dan Higgins" <djh@sgi.com>, "Jeremy Higdon" <jeremy@sgi.com>
Subject: Re: [PATCH] ia64: change usermode HZ to 250
Date: Wed, 28 Jun 2006 08:43:46 -0700	[thread overview]
Message-ID: <005e01c69ac9$a55e1bf0$6f00a8c0@comcast.net> (raw)
In-Reply-To: 1151483994.3153.5.camel@laptopd505.fenrus.org

From: "Arjan van de Ven" <arjan@infradead.org>
...
> ok why not define the userspace HZ to
>
> #define HZ sysconf(_SC_CLK_TCK)

That did occur to me.  It obviously does get the correct value.  The downside
is that one of those crufty apps that thinks it is using "HZ" as a constant
will instead be invoking a more costly syscall.  Should we care about the
resulting performance impact?

I vote for Arjan's solution.

John Hawkes


  reply	other threads:[~2006-06-28 15:43 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-27 22:01 [PATCH] ia64: change usermode HZ to 250 hawkes
2006-06-27 22:01 ` hawkes
2006-06-27 22:26 ` Luck, Tony
2006-06-27 22:26   ` Luck, Tony
2006-06-27 23:09   ` Lee Revell
2006-06-27 23:09     ` Lee Revell
2006-06-28  8:43   ` Arjan van de Ven
2006-06-28  8:43     ` Arjan van de Ven
2006-06-28 10:47     ` Alan Cox
2006-06-28 10:47       ` Alan Cox
2006-06-28 10:34       ` Arjan van de Ven
2006-06-28 10:34         ` Arjan van de Ven
2006-06-28 14:46         ` Christoph Lameter
2006-06-28 14:46           ` Christoph Lameter
2006-06-28  8:39 ` Arjan van de Ven
2006-06-28  8:39   ` Arjan van de Ven
2006-06-28 15:43   ` John Hawkes [this message]
2006-06-28 15:43     ` John Hawkes
2006-06-28 16:21     ` Alan Cox
2006-06-28 16:21       ` Alan Cox
2006-06-28 16:11       ` John Daiker
2006-06-28 16:11         ` John Daiker
2006-06-28 16:50         ` Alan Cox
2006-06-28 16:50           ` Alan Cox
2006-06-28 17:36 ` Luck, Tony
2006-06-28 17:36   ` Luck, Tony
2006-06-29  9:37   ` Jes Sorensen
2006-06-29  9:37     ` Jes Sorensen
2006-06-29 10:46     ` Alan Cox
2006-06-29 11:02       ` Alan Cox
2006-06-29 10:48       ` Jes Sorensen
2006-06-29 10:48         ` Jes Sorensen
2006-06-29 10:55         ` Arjan van de Ven
2006-06-29 10:55           ` Arjan van de Ven
2006-06-29 12:56           ` Jes Sorensen
2006-06-29 12:56             ` Jes Sorensen
2006-07-08  0:14           ` Jeremy Higdon
2006-07-08  0:14             ` Jeremy Higdon
2006-07-08  2:51             ` Tony Luck
2006-07-08  2:51               ` Tony Luck
2006-07-08  6:42             ` Arjan van de Ven
2006-07-08  6:42               ` Arjan van de Ven
2006-07-08 13:07               ` David Mosberger-Tang
2006-07-08 13:07                 ` David Mosberger-Tang
2006-07-10 20:22                 ` Jeremy Higdon
2006-07-10 20:22                   ` Jeremy Higdon
2006-07-11  3:01                   ` David Mosberger-Tang
2006-07-11  3:01                     ` David Mosberger-Tang
2006-07-11  9:53                     ` Alan Cox
2006-07-11 10:10                       ` Alan Cox
2006-07-11 18:37                     ` Jeremy Higdon
2006-07-11 18:37                       ` Jeremy Higdon
2006-07-12  2:02                       ` David Mosberger-Tang
2006-07-12  2:02                         ` David Mosberger-Tang
2006-06-29 11:34         ` Alan Cox
2006-06-29 11:34           ` Alan Cox
2006-06-29 14:09 ` Albert Cahalan
2006-06-29 14:09   ` Albert Cahalan
2006-07-09 19:18 ` Luck, Tony
2006-07-09 19:18   ` Luck, Tony

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