From owner-freebsd-current@FreeBSD.ORG Sun Dec 14 19:20:46 2014 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id AC7D6A86; Sun, 14 Dec 2014 19:20:46 +0000 (UTC) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 66BAC2C3; Sun, 14 Dec 2014 19:20:46 +0000 (UTC) Received: from slw by zxy.spb.ru with local (Exim 4.84 (FreeBSD)) (envelope-from ) id 1Y0Eig-0005OJ-2B; Sun, 14 Dec 2014 23:20:42 +0400 Date: Sun, 14 Dec 2014 23:20:42 +0400 From: Slawa Olhovchenkov To: Ian Lepore Subject: Re: simple task to speed up booting Message-ID: <20141214192041.GA48237@zxy.spb.ru> References: <43445.1418553160@critter.freebsd.dk> <1418568731.935.8.camel@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1418568731.935.8.camel@freebsd.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false Cc: Poul-Henning Kamp , current@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 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: Sun, 14 Dec 2014 19:20:46 -0000 On Sun, Dec 14, 2014 at 07:52:11AM -0700, Ian Lepore wrote: > On Sun, 2014-12-14 at 10:32 +0000, Poul-Henning Kamp wrote: > > The rotating swirlie ('-/|\') in the loader accounts for a surprisingly > > large part of our boot time on systems with slow-ish serial consoles. > > > > I think right now it takes a step for each 512 byte read, reducing that > > to once every 64kB or even 1MB would be an improvement with the kind of > > kernel sizes we have today. > > > > I experimented with that a while ago using the attached patch and was > disappointed with the results. As I vaguely remember it, a divisor of 8 > looked fine, but had no significant speedup. With a divisor of 32 the > difference was measureable (only like 1.5 seconds or so faster), but it > gave the impression that something was wrong, and the overall perception > was that it was slower rather than faster, despite what a stopwatch > said. > > I was testing at 115kbps, maybe at 9600 it would be significant. I > don't understand why anything these days is still defaulting to 9600. > It's the 21st century, but we never got the George Jetson flying cars we > were promised, and apparently we're never going to break loose from the > standards set by accoustic-coupled modems. You not always working with self-owned servers. Default is 9600,8n1