From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751382AbWF1Qeg (ORCPT ); Wed, 28 Jun 2006 12:34:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751412AbWF1Qeg (ORCPT ); Wed, 28 Jun 2006 12:34:36 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:14274 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S1751382AbWF1Qee (ORCPT ); Wed, 28 Jun 2006 12:34:34 -0400 Subject: Re: [PATCH] ia64: change usermode HZ to 250 From: Alan Cox To: John Daiker Cc: John Hawkes , Arjan van de Ven , Tony Luck , Andrew Morton , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, Jack Steiner , Dan Higgins , Jeremy Higdon In-Reply-To: <44A2AA2B.3090101@osdl.org> References: <20060627220139.3168.69409.sendpatchset@tomahawk.engr.sgi.com> <1151483994.3153.5.camel@laptopd505.fenrus.org> <005e01c69ac9$a55e1bf0$6f00a8c0@comcast.net> <1151511668.15166.34.camel@localhost.localdomain> <44A2AA2B.3090101@osdl.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Wed, 28 Jun 2006 17:50:38 +0100 Message-Id: <1151513438.15166.41.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ar Mer, 2006-06-28 am 09:11 -0700, ysgrifennodd John Daiker: > people should have been using the syscall to begin with... we're just > forcing it on them this way! :-) That's my $0.02 In the cached HZ case there will be no performance hit of measure anyway. The bigger problem is existing user space. That is why we've always kept the user visible HZ based values the same when changing the kernel HZ. You can't automatically regenerate all the old binaries you might otherwise break. Performance is only a minor issue, and I doubt anyone who cared about performance would be using ia-64 anyway [Grabs coat and exits..]