From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 2/5] kvmtrace: make cycle calculation architecture aware Date: Sun, 13 Jul 2008 18:41:04 +0300 Message-ID: <487A2210.5020602@qumranet.com> References: <1215439013-11480-1-git-send-email-ehrhardt@linux.vnet.ibm.com> <4874821F.4060509@linux.vnet.ibm.com> <1215615799.22935.1.camel@localhost.localdomain> <200807101822.16163.sheng.yang@intel.com> <48760F6D.5000709@qumranet.com> <48770CEF.6090102@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "Yang, Sheng" , kvm@vger.kernel.org, Hollis Blanchard , Christian Ehrhardt , xiantao.zhang@intel.com, kvm-ppc@vger.kernel.org To: carsteno@de.ibm.com Return-path: Received: from il.qumranet.com ([212.179.150.194]:55209 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751547AbYGMPlF (ORCPT ); Sun, 13 Jul 2008 11:41:05 -0400 In-Reply-To: <48770CEF.6090102@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: Carsten Otte wrote: > Avi Kivity wrote: >> What is the overhead of ktime_get()? > I think I'd like an arch specific timestamp. This way we could use our > clock-cycle-granularity-non-privileged-timestamp instruction ;-). If > we need a common implementation, I don't think there's much difference > between different syscalls in terms of overhead. This is all in-kernel, so no syscalls. Since I doubt you need sub-ns granularity for kvmtrace, can we do without an arch hook? -- error compiling committee.c: too many arguments to function