From owner-freebsd-hackers Mon Nov 3 19:58:55 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id TAA05185 for hackers-outgoing; Mon, 3 Nov 1997 19:58:55 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from srv.net (snake.srv.net [199.104.81.3]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id TAA05170 for ; Mon, 3 Nov 1997 19:58:51 -0800 (PST) (envelope-from cmott@srv.net) Received: from darkstar.home ([208.141.171.158]) by srv.net (8.8.5/8.8.5) with SMTP id UAA08194 for ; Mon, 3 Nov 1997 20:58:49 -0700 (MST) Date: Mon, 3 Nov 1997 20:58:15 -0700 (MST) From: Charles Mott X-Sender: cmott@darkstar.home Reply-To: Charles Mott To: freebsd-hackers@freebsd.org Subject: gettimeofday() overhead Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk In the packet aliasing code used by natd and ppp -alias, gettimeofday() is called for every packet. I think this involves a kernel context switch (correct me if I am wrong) and tests I did a while ago showed something like 60 or 70 microseconds per call on a 386. Since timing measurements don't have to be particularly accurate for libalias, does anyone have an idea how time might be measured entirely in user space? Charles Mott