From owner-freebsd-current@FreeBSD.ORG Wed Nov 30 02:13:15 2005 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2624116A487 for ; Wed, 30 Nov 2005 02:13:15 +0000 (GMT) (envelope-from ivoras@fer.hr) Received: from pinus.cc.fer.hr (pinus.cc.fer.hr [161.53.73.18]) by mx1.FreeBSD.org (Postfix) with ESMTP id 95C1843D6B for ; Wed, 30 Nov 2005 02:13:12 +0000 (GMT) (envelope-from ivoras@fer.hr) Received: from [161.53.72.113] (lara.cc.fer.hr [161.53.72.113]) by pinus.cc.fer.hr (8.12.2/8.12.2) with ESMTP id jAU2D6Fx020257; Wed, 30 Nov 2005 03:13:07 +0100 (MET) Message-ID: <438D0A93.2080001@fer.hr> Date: Wed, 30 Nov 2005 03:12:35 +0100 From: Ivan Voras User-Agent: Mozilla Thunderbird 1.0.6 (X11/20050921) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Poul-Henning Kamp , current@freebsd.org References: <6592.1133215884@critter.freebsd.dk> In-Reply-To: <6592.1133215884@critter.freebsd.dk> Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: Re: proof-of-concept patch for cpu accounting speedup X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Nov 2005 02:13:15 -0000 Poul-Henning Kamp wrote: > I am very interested to hear feedback and benchmarks of this patch. So, here are some :) I've applied your patch to 6-stable with only minor difficulties. Here are the results of unixbench's context1 benchmark for "normal" (unpatched) kernel with acpi-fast, tsc and i8254 timecounter hardware and then with a patched kernel (timecounter hardware didn't make a noticable difference here): x ct1-6-stable-tsc + ct1-6-stable-tscphk * ct1-6-stable-acpifast % ct1-6-stable-i8254 +--------------------------------------------------------------------------+ |% * | |% * | |% * x +| |% * xx ++| |% * xx ++| |A A A| |A| +--------------------------------------------------------------------------+ N Min Max Median Avg Stddev x 5 2331645 2353665 2342346 2342657.8 9825.4048 + 5 2585053 2605310 2602141 2596283.8 10010.176 Difference at 95.0% confidence 253626 +/- 14465.2 10.8264% +/- 0.617468% (Student's t, pooled s = 9918.22) * 5 1719124 1727693 1725060 1724709.8 3464.6507 Difference at 95.0% confidence -617948 +/- 10744.2 -26.3781% +/- 0.458633% (Student's t, pooled s = 7366.9) % 5 582065 584233 582435 582720 883.62832 Difference at 95.0% confidence -1.75994e+06 +/- 10173.6 -75.1257% +/- 0.434275% (Student's t, pooled s = 6975.65) Also, I did complete runs of unixbench and here are the cumulative indexes: unpatched-acpi-fast: 326.7 unpatched-tsc: 336.3 patched+tsc: 349.1 By this benchmark, it seems that overall performance could improve by ~7% by using your patch vs the default acpi-fast timecounter on unpatched kernel. Of course, this result probably won't hold in real life :) All results are available at: http://ivoras.sharanet.org/stuff/timebench.tgz