Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262169AbUKKEfN (ORCPT ); Wed, 10 Nov 2004 23:35:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262172AbUKKEfN (ORCPT ); Wed, 10 Nov 2004 23:35:13 -0500 Received: from relay03.pair.com ([209.68.5.17]:40464 "HELO relay03.pair.com") by vger.kernel.org with SMTP id S262169AbUKKEey (ORCPT ); Wed, 10 Nov 2004 23:34:54 -0500 X-pair-Authenticated: 24.241.238.70 Message-ID: <4192EBE9.60300@cybsft.com> Date: Wed, 10 Nov 2004 22:34:49 -0600 From: "K.R. Foley" User-Agent: Mozilla Thunderbird 0.9 (X11/20041103) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ingo Molnar CC: linux-kernel@vger.kernel.org, Lee Revell , Rui Nuno Capela , Mark_H_Johnson@Raytheon.com, Bill Huey , Adam Heath , Florian Schmidt , Thomas Gleixner , Michal Schmidt , Fernando Pablo Lopez-Lezcano , Karsten Wiese , Gunther Persoons , emann@mrv.com, Shane Shrybman , Amit Shah Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc1-mm3-V0.7.23 References: <20041021132717.GA29153@elte.hu> <20041022133551.GA6954@elte.hu> <20041022155048.GA16240@elte.hu> <20041022175633.GA1864@elte.hu> <20041025104023.GA1960@elte.hu> <20041027001542.GA29295@elte.hu> <20041103105840.GA3992@elte.hu> <20041106155720.GA14950@elte.hu> <20041108091619.GA9897@elte.hu> <20041108165718.GA7741@elte.hu> <20041109160544.GA28242@elte.hu> In-Reply-To: <20041109160544.GA28242@elte.hu> X-Enigmail-Version: 0.86.0.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2665 Lines: 67 Ingo Molnar wrote: > i have released the -V0.7.23 Real-Time Preemption patch, which can be > downloaded from the usual place: > > http://redhat.com/~mingo/realtime-preempt/ > I have found some test results that I find interesting with -V0.7.24. I modified the rtc-debug patch to work with any program that can use the rtc driver. It measures the latency between handling an interrupt and the actual read. The amlat program normally used with this patch sets up a signal handler that reads /dev/rtc when there is data available and then sleeps until it receives the signal. Realfeel just does a blocking read on /dev/rtc. Oh and both of them setup the rtc for periodic interrupts. I would probably expect the blocking read to be a bit faster but not dramatically. Here are the results of a couple of very short runs to illustrate the difference: amlat results (sleep/sighandler): Nov 10 21:10:39 daffy kernel: rtc histogram: Nov 10 21:10:39 daffy kernel: 26 1 Nov 10 21:10:39 daffy kernel: 28 2152 Nov 10 21:10:39 daffy kernel: 29 4286 Nov 10 21:10:39 daffy kernel: 30 6857 Nov 10 21:10:39 daffy kernel: 31 408 Nov 10 21:10:39 daffy kernel: 32 9 Nov 10 21:10:39 daffy kernel: 33 32 Nov 10 21:10:39 daffy kernel: 34 217 Nov 10 21:10:39 daffy kernel: 35 145 Nov 10 21:10:39 daffy kernel: 36 26 Nov 10 21:10:39 daffy kernel: 40 2 Nov 10 21:10:39 daffy kernel: 41 9 Nov 10 21:10:39 daffy kernel: 42 100 Nov 10 21:10:39 daffy kernel: 43 180 Nov 10 21:10:39 daffy kernel: 44 113 Nov 10 21:10:39 daffy kernel: 45 30 Nov 10 21:10:39 daffy kernel: 46 2 Nov 10 21:10:39 daffy kernel: 47 4 Nov 10 21:10:39 daffy kernel: 48 15 Nov 10 21:10:39 daffy kernel: 49 4 Nov 10 21:10:39 daffy kernel: 50 5 Nov 10 21:10:39 daffy kernel: Nov 10 21:10:39 daffy kernel: Total samples: 14597 realfeel results (blocking read): Nov 10 21:11:32 daffy kernel: rtc histogram: Nov 10 21:11:32 daffy kernel: 3 17844 Nov 10 21:11:32 daffy kernel: 4 859 Nov 10 21:11:32 daffy kernel: 5 34 Nov 10 21:11:32 daffy kernel: 6 1 Nov 10 21:11:32 daffy kernel: 8 1 Nov 10 21:11:32 daffy kernel: 12 19 Nov 10 21:11:32 daffy kernel: 13 41 Nov 10 21:11:32 daffy kernel: 14 7 Nov 10 21:11:32 daffy kernel: Nov 10 21:11:32 daffy kernel: Total samples: 18806 Both of the above runs were with 'IRQ 8' running at SCHED_FF 99. Amlat and realfeel were both running at SCHED_FF 98. The updated rtc-debug patch to follow in case anyone is interested. kr - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/