From owner-freebsd-hackers@FreeBSD.ORG Fri May 29 18:53:40 2015 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id ED3DC5C9; Fri, 29 May 2015 18:53:40 +0000 (UTC) (envelope-from sebastian.huber@embedded-brains.de) Received: from mail.embedded-brains.de (host-82-135-62-35.customer.m-online.net [82.135.62.35]) (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 8C338110D; Fri, 29 May 2015 18:53:39 +0000 (UTC) (envelope-from sebastian.huber@embedded-brains.de) Received: from localhost (localhost.localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id 0C0CE2A1820; Fri, 29 May 2015 20:54:18 +0200 (CEST) Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id Vzbz-ti-QsIH; Fri, 29 May 2015 20:54:16 +0200 (CEST) Received: from localhost (localhost.localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id C68992A1930; Fri, 29 May 2015 20:54:16 +0200 (CEST) X-Virus-Scanned: amavisd-new at zimbra.eb.localhost Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id DPmLLfVsp8Mm; Fri, 29 May 2015 20:54:16 +0200 (CEST) Received: from zimbra.eb.localhost (zimbra.eb.localhost [192.168.96.204]) by mail.embedded-brains.de (Postfix) with ESMTP id AD1C22A1820; Fri, 29 May 2015 20:54:16 +0200 (CEST) Date: Fri, 29 May 2015 20:54:16 +0200 (CEST) From: Sebastian Huber To: Poul-Henning Kamp Cc: freebsd-hackers@freebsd.org Message-ID: <1056382604.51315.1432925656612.JavaMail.zimbra@embedded-brains.de> In-Reply-To: <85619.1432920847@critter.freebsd.dk> References: <55686300.3080100@embedded-brains.de> <85086.1432906578@critter.freebsd.dk> <55686C0F.9000101@embedded-brains.de> <85121.1432906871@critter.freebsd.dk> <55686D31.1060408@embedded-brains.de> <85619.1432920847@critter.freebsd.dk> Subject: Re: Problem with timecounters and memory model MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [192.168.102.3] X-Mailer: Zimbra 8.6.0_GA_1153 (zclient/8.6.0_GA_1153) Thread-Topic: Problem with timecounters and memory model Thread-Index: EEpMDTpL6n79A8Z26bs4W/73GgMEmg== X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 May 2015 18:53:41 -0000 ----- Poul-Henning Kamp schrieb: > -------- > In message <55686D31.1060408@embedded-brains.de>, Sebastian Huber writes: >=20 > >> How often do you "wind" the timecounter ? > > > >More often than necessary. About 1000 times a second with only one=3D20 > >timehand (this is a hack to support legacy systems). The test case is: >=20 > If you only have one timehand, I can't see how it can work without > locks ? In RTEMS we have two build time configurations: uni-processor and SMP. In = the uni-processor configuration we have only one timehand. The windup func= tion is called in interrupt context with interrupts disabled. We have the = one timehand limitation since not every supported hardware provides a free = running counter. In the SMP configuration we use the default 10 timehands. --=20 Sebastian Huber, embedded brains GmbH Address : Dornierstr. 4, D-82178 Puchheim, Germany Phone : +49 89 189 47 41-16 Fax : +49 89 189 47 41-09 E-Mail : sebastian.huber at embedded-brains.de PGP : Public key available on request. Diese Nachricht ist keine gesch=C3=A4ftliche Mitteilung im Sinne des EHUG.