Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762115AbYCDB3c (ORCPT ); Mon, 3 Mar 2008 20:29:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755651AbYCDB3W (ORCPT ); Mon, 3 Mar 2008 20:29:22 -0500 Received: from smtp117.sbc.mail.sp1.yahoo.com ([69.147.64.90]:47971 "HELO smtp117.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755550AbYCDB3V (ORCPT ); Mon, 3 Mar 2008 20:29:21 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=IygLSCPR3IobrgonCa/4hKmey2ts/MB7jGmCOZp7NxceK7dOM5JX0DQTubBKWW1gJ6xajyJIT5aJ7V95esyc+ju4QGFlkU+tmx7FVUpD6Gq1x6BXikPxbp0qabdvbxy6wcJlr+RBFS6CdS7wNVX+icHwHmINSUj5dQYjcxOYUr4= ; X-YMail-OSG: zrGodwsVM1mfUxy3xGdYifEMbHQlS563js8pe7vGnxpmrvvE0aEXNAdItWgbcS_x5IneroQK7Q-- X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: "Bosko Radivojevic" Subject: Re: High resolution timers on AT91SAM926x Date: Mon, 3 Mar 2008 17:29:18 -0800 User-Agent: KMail/1.9.6 Cc: lkml , linux-rt-users@vger.kernel.org, tglx@linutronix.de References: <200803011457.40857.david-b@pacbell.net> <200803031039.57909.david-b@pacbell.net> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200803031729.19264.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1052 Lines: 28 On Monday 03 March 2008, Bosko Radivojevic wrote: > I had CONFIG_ATMEL_TCLIB enabled, but not TCB_CLKSRC and > TCB_CLKSRC_BLOCK=0. With all those options, I finally have HRT > functionality. But, strange thing is that jitter of my little example > (get time, sleep 1ms, get time, show the difference) is around 250us. > Maybe this is normal for this architecture? I have no idea why that would be. Maybe you can find out. :) > System is (as noted on rt.wik site) very slow with NO_HZ option enabled. It doesn't exactly say *why* or compare to other arm926ejs chips ... Could the 64-bit math (ktime stuff) be a factor there? Your board probably only runs at 95 (or-so) bogomips after all. And is that just a NO_HZ issue, or generically an issue when oneshot timer modes are in heavy use? - Dave -- 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/