Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 9 Apr 2001 06:25:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 9 Apr 2001 06:25:15 -0400 Received: from delta.ds2.pg.gda.pl ([213.192.72.1]:24456 "EHLO delta.ds2.pg.gda.pl") by vger.kernel.org with ESMTP id ; Mon, 9 Apr 2001 06:25:10 -0400 Date: Mon, 9 Apr 2001 12:02:54 +0200 (MET DST) From: "Maciej W. Rozycki" To: Ivan Kokshaysky cc: "Eric W. Biederman" , Geert Uytterhoeven , James Simmons , Alan Cox , Linux Fbdev development list , Linux Kernel Mailing List Subject: Re: [Linux-fbdev-devel] Re: fbcon slowness [was NTP on 2.4.2?] In-Reply-To: <20010408221123.A22893@jurassic.park.msu.ru> Message-ID: Organization: Technical University of Gdansk MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 8 Apr 2001, Ivan Kokshaysky wrote: > Of course. I meant that if you are reading, for example, some status register > in a loop waiting for "ready bit" set, the memory barrier won't help you > to notice this event any faster. Actually you'll notice that *later*, as > "mb" is expensive. I think you need an mb here. To force sychronization with other CPUs. Unless you know you are UP or there is no possibility another CPU may access the relevant device. Of course mbs hit performance but it's a trade off for coherency. -- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available + - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/