From owner-freebsd-current@FreeBSD.ORG Tue Jun 14 15:54:48 2011 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C59B0106564A for ; Tue, 14 Jun 2011 15:54:48 +0000 (UTC) (envelope-from luigi@onelab2.iet.unipi.it) Received: from onelab2.iet.unipi.it (onelab2.iet.unipi.it [131.114.59.238]) by mx1.freebsd.org (Postfix) with ESMTP id 9199F8FC0A for ; Tue, 14 Jun 2011 15:54:48 +0000 (UTC) Received: by onelab2.iet.unipi.it (Postfix, from userid 275) id A9B517300A; Tue, 14 Jun 2011 18:11:05 +0200 (CEST) Date: Tue, 14 Jun 2011 18:11:05 +0200 From: Luigi Rizzo To: current@freebsd.org Message-ID: <20110614161105.GA17306@onelab2.iet.unipi.it> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.3i Cc: Subject: fast/syscall-free gettimeofday ? 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: Tue, 14 Jun 2011 15:54:48 -0000 there were discussions at some point on an imprecise but fast implementations of gettimeofday() that would not require a system call (perhaps mmapping some memory region which is opportunistically updated). Does anyone remember what happened about that ? Otherwise, is there any place in the kernel where i can fetch a struct timeval which is not off by more than, say 1 tick ? cheers luigi