From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 20 Apr 2009 09:02:14 +0100 (BST) Received: from localhost.localdomain ([127.0.0.1]:7390 "EHLO h5.dl5rb.org.uk") by ftp.linux-mips.org with ESMTP id S20026403AbZDTICK (ORCPT ); Mon, 20 Apr 2009 09:02:10 +0100 Received: from h5.dl5rb.org.uk (localhost.localdomain [127.0.0.1]) by h5.dl5rb.org.uk (8.14.3/8.14.3) with ESMTP id n3K81xIX012364; Mon, 20 Apr 2009 10:02:00 +0200 Received: (from ralf@localhost) by h5.dl5rb.org.uk (8.14.3/8.14.3/Submit) id n3K81tZc012363; Mon, 20 Apr 2009 10:01:55 +0200 Date: Mon, 20 Apr 2009 10:01:55 +0200 From: Ralf Baechle To: Wu Zhangjin Cc: Zhang Le , linux-kernel@vger.kernel.org, Nicholas Mc Guire , Ingo Molnar , Thomas Gleixner , zhangfx@lemote.com, loongson-dev@googlegroups.com, yanh@lemote.com, linux-mips@linux-mips.org, linux-rt-users@vger.kernel.org Subject: Re: "RT_PREEMPT for loongson" is updated to patch-2.6.29.1-rt8 Message-ID: <20090420080155.GA11621@linux-mips.org> References: <1240193547.25532.52.camel@falcon> <20090420050419.GA22520@adriano.hkcable.com.hk> <1240211926.8884.27.camel@falcon> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1240211926.8884.27.camel@falcon> User-Agent: Mutt/1.5.18 (2008-05-17) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 22380 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Mon, Apr 20, 2009 at 03:18:46PM +0800, Wu Zhangjin wrote: > On Mon, 2009-04-20 at 13:04 +0800, Zhang Le wrote: > to Ralf, > > I have divided ftrace to several commits in the above git tree, hope you > can check it, thx :-) > > in addition to the static/dynamic/graph function tracer & system call > tracer implementation, a mips specific ring_buffer_time_stamp > (kernel/trace/ring_buffer.c) is also implemented to get 1us precision > time, this is very important to make ftrace available in mips, > otherwise, we can only get 1ms precision time for the original > ring_buffer_time_stamp is based on sched_clock(jiffies based). > > perhaps we can implement a more precise sched_clock directly, just as > x86 does(native_sched_clock, tsc based), but in mips, there is only a > 32bit timer count which will quickly overflow, so it will need an extra > overflow protection, which may influence the other parts of the kernel. My git clone is still running to I'm commenting only on the patches you posted earlier. #ifdef-MIPS'ing things into the generic kernel code definately won't be an acceptable way to get µs resolution. Ralf