From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Date: Wed, 28 Jun 2006 08:39:54 +0000 Subject: Re: [PATCH] ia64: change usermode HZ to 250 Message-Id: <1151483994.3153.5.camel@laptopd505.fenrus.org> List-Id: References: <20060627220139.3168.69409.sendpatchset@tomahawk.engr.sgi.com> In-Reply-To: <20060627220139.3168.69409.sendpatchset@tomahawk.engr.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: hawkes@sgi.com Cc: Tony Luck , Andrew Morton , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Jack Steiner , Dan Higgins , Jeremy Higdon On Tue, 2006-06-27 at 15:01 -0700, hawkes@sgi.com wrote: > include/asm-ia64/param.h defines HZ to be 1024 for usermode use, i.e., > when the file gets installed as /usr/include/asm/param.h. > As the comment says: > Technically, this is wrong, but some old apps still refer to it. > The proper way to get the HZ value is via sysconf(_SC_CLK_TCK). > At the very least, this technically wrong #define ought to reflect the > current default value (250) used by all arch/ia64 platforms. No one uses > 1024 anymore. This makes those "old apps" (e.g., usr/bin/iostat) behave > properly for with a default kernel. (And at some point, the define ought > to be removed altogether, which would expose all the applications that > erroneously expect HZ to be a compile-time constant.) > > Signed-off-by: John Hawkes > > Index: linux/include/asm-ia64/param.h > =================================> --- linux.orig/include/asm-ia64/param.h 2006-06-17 18:49:35.000000000 -0700 > +++ linux/include/asm-ia64/param.h 2006-06-27 14:46:53.119407077 -0700 > @@ -36,7 +36,7 @@ > * Technically, this is wrong, but some old apps still refer to it. The proper way to > * get the HZ value is via sysconf(_SC_CLK_TCK). > */ > -# define HZ 1024 > +# define HZ 250 > #endif ok why not define the userspace HZ to #define HZ sysconf(_SC_CLK_TCK) ?