From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751074AbWGZQIv (ORCPT ); Wed, 26 Jul 2006 12:08:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751210AbWGZQIv (ORCPT ); Wed, 26 Jul 2006 12:08:51 -0400 Received: from ug-out-1314.google.com ([66.249.92.169]:49194 "EHLO ug-out-1314.google.com") by vger.kernel.org with ESMTP id S1751074AbWGZQIs (ORCPT ); Wed, 26 Jul 2006 12:08:48 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=sBdTfGOgF0De+TwZdmlo9Ri2nS04mFRtHZ7Ewq03wDr3SoAlwMWEgyfSHXQGOlBjEH0kcdu+MQiDGTVirkCWQ7z16rZ2SUr8oZ50/Mf1/CzHzV3hntBN530ryvzKushGMDEWuKjuHzKanqsJyc5odo6i9gr1htyKlwTZGFOdWr8= Message-ID: <1f1b08da0607260908u753684c5ocda8b361db65227b@mail.gmail.com> Date: Wed, 26 Jul 2006 09:08:46 -0700 From: "john stultz" To: "John Richard Moser" Subject: Re: gettimeofday(), clock_gettime(), timer_gettime() Cc: linux-kernel@vger.kernel.org In-Reply-To: <44C6D8CD.4040604@comcast.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <44C6D8CD.4040604@comcast.net> X-Google-Sender-Auth: 4c78cf1bb84d2698 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 7/25/06, John Richard Moser wrote: > I'm looking through a few things and noticing some complaints about time > and performance. Briefly, the following things have come to my attention: > > - gettimeofday() is slow, or so they say, needing several milliseconds > to execute. No. At worse its several microseconds (PIT takes about 18us, and its terrible!). More likely you'll see ~1us using ACPI PM or HPET or ~500-100ns (depending on your system). With vsyscall it can get into the sub 100ns range. thanks -john