Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753744AbZKBDNs (ORCPT ); Sun, 1 Nov 2009 22:13:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753585AbZKBDNs (ORCPT ); Sun, 1 Nov 2009 22:13:48 -0500 Received: from mail-pw0-f42.google.com ([209.85.160.42]:54708 "EHLO mail-pw0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753455AbZKBDNr (ORCPT ); Sun, 1 Nov 2009 22:13:47 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=s1AE+dkwrEgQA+fosNxg2iUdJLvkOMJY69oAlAtQxkU7XeuiPpL5y6ITs6FuOS3OEb Sx8Taj2A6IMKc7TSnt6Q/LbqP/aHTq6eZ2zESPcxYFx6/p6752nL4rRkTzROI31WoCsd IlHPEIfYlkBNKQtQVjetE/xu53UUMR4O92+MM= MIME-Version: 1.0 Date: Mon, 2 Nov 2009 11:13:51 +0800 Message-ID: <3a665c760911011913q268b010cqb5da4f79df995b9b@mail.gmail.com> Subject: why kernel implement "udelay" by cpu instructions? From: loody To: linux-kernel@vger.kernel.org, Kernel Newbies Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 525 Lines: 13 Dear all: I find the kernel use cpu instruction to implement the udelay function as keeping decrease a big counter by 1. If I search the right place in kernel, why kernel does so? the precision will be different if cpu runs faster or slower, right? appreciate your help, miloody -- 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/