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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>
References: <20060627220139.3168.69409.sendpatchset@tomahawk.engr.sgi.com> <1151483994.3153.5.camel@laptopd505.fenrus.org>
Subject: Re: [PATCH] ia64: change usermode HZ to 250
Date: Wed, 28 Jun 2006 08:43:46 -0700
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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