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Message-ID: <ed5aea430607111902i91b9e92s784ce8d2103f1b4e@mail.gmail.com>
Date: Tue, 11 Jul 2006 20:02:37 -0600
From: "David Mosberger-Tang" <David.Mosberger@acm.org>
To: "Jeremy Higdon" <jeremy@sgi.com>
Subject: Re: [PATCH] ia64: change usermode HZ to 250
Cc: "Arjan van de Ven" <arjan@infradead.org>, "Jes Sorensen" <jes@sgi.com>,
       "Alan Cox" <alan@lxorguk.ukuu.org.uk>,
       "Luck, Tony" <tony.luck@intel.com>, "John Daiker" <jdaiker@osdl.org>,
       "John Hawkes" <hawkes@sgi.com>, "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>
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On 7/11/06, Jeremy Higdon <jeremy@sgi.com> wrote:

> Okay.  So what do you think about changing the value in param.h from
> 1024, so that it matches the new common value of 250, or is it best
> just to leave it at 1024 and let applications that use it get the wrong
> result?

In my opinion, HZ needs to be a constant, since otherwise you could
break perfectly fine existing code (e.g., code which statically
initializes a variable with HZ and then picks up the correct frequency
from sysconf) and if you have to pick a particular constant, it seems
reasonable to me to pick the most commonly used frequency (which
appears to be 250Hz at the moment).

  --david
-- 
Mosberger Consulting LLC, http://www.mosberger-consulting.com/