From owner-freebsd-performance@FreeBSD.ORG Fri Jan 2 23:15:07 2015 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 6FF55FDB for ; Fri, 2 Jan 2015 23:15:07 +0000 (UTC) Received: from mail-oi0-x232.google.com (mail-oi0-x232.google.com [IPv6:2607:f8b0:4003:c06::232]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 2E11F1A6A for ; Fri, 2 Jan 2015 23:15:07 +0000 (UTC) Received: by mail-oi0-f50.google.com with SMTP id x69so41797280oia.9 for ; Fri, 02 Jan 2015 15:15:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=9p4Fqn+Mk32XnpLJouygVGzbfU40FwaeFo3S1r/dipo=; b=H0fmI5uPRN3ORHfMDBpK/p4XFCBf0QJxYvst68CvxUtfU3spuD53kAO/17N5wWomP1 g5Gp+2VoUO5WFoaxnZe9MKgem3U0QhiAdCt0Hbv1F5wUoHYDo3xVHzrizbcuuwb4e2wm HL8AQjQAeGBAYmd1EGvf/LgddenuV44gREVmwqx8hN/eYAef+EX+iTD0FDVZDJ39uIrv fVMrt0s0fjsYia0XBimvry1+XLsXKf0fq4eYCWFaq2TttFNsJdmC+2HP8xkYAlDc8Xgw FotlBUnIVkG91j0+DDdMZWbdootxEFgyFK52hiDzsT9hmj0Rp4liH68yIaYBS+/y0YVp lEhg== MIME-Version: 1.0 X-Received: by 10.202.46.196 with SMTP id u187mr43535574oiu.19.1420240506571; Fri, 02 Jan 2015 15:15:06 -0800 (PST) Received: by 10.60.102.241 with HTTP; Fri, 2 Jan 2015 15:15:06 -0800 (PST) In-Reply-To: <20150102172447.GT42409@kib.kiev.ua> References: <54A43EC4.2030706@mykolab.com> <9BF461F5-D6B6-4287-BE8B-87B281FE93D0@gmail.com> <20150101033733.4b295d3b@schwanenlied.me> <54A621C2.2060408@mykolab.com> <20150102102036.0a52b072@schwanenlied.me> <20150102172447.GT42409@kib.kiev.ua> Date: Fri, 2 Jan 2015 18:15:06 -0500 Message-ID: Subject: Re: Fwd: [tor-dev] gettimeofday() Syscall Issues From: grarpamp To: freebsd-performance@freebsd.org Content-Type: text/plain; charset=UTF-8 Cc: tor-dev@lists.torproject.org X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Jan 2015 23:15:07 -0000 On Fri, Jan 2, 2015 at 12:24 PM, Konstantin Belousov wrote: > On Fri, Jan 02, 2015 at 09:09:34AM -0500, grarpamp wrote: >> Some recent FreeBSD related questions in this app area. >> > What is the question ? > > As a background, I can repeat that FreeBSD implements syscall-less > gettimeofday() and clock_gettime() for x86 machines which have > usable RDTSC. The selection of the timecounter can be verified > by sysctl kern.timecounter.hardware, and enabled by default fast > gettimeofday(2) can be checked by sysctl kern.timecounter.fast_gettime. > > On some Nehalem machine, I see it doing ~30M calls/sec with enabled > fast_gettime, and ~6.25M calls/sec with disabled fast_gettime. This is > measured on 2.8GHz Core i7 930 with src/tools/tools/syscall_timing. > > Check your timecounter hardware. Since it was noted that the tests > were done in VM, check the quality of RDTSC emulation in your hypervisor. https://lists.torproject.org/pipermail/tor-dev/2015-January/thread.html http://docs.freebsd.org/mail/current/freebsd-performance.html Maybe I can just refer non subscribers out to the two lists above that way in case anyone sees anything interesting they can join/comment as desired. Background might be that Tor operators have some large relays on *BSD and were looking to validate, and ways to improve, performance there. Cheers. https://lists.torproject.org/pipermail/tor-relays/ https://lists.torproject.org/pipermail/tor-talk/