From owner-freebsd-alpha Thu Sep 5 8:22:24 2002 Delivered-To: freebsd-alpha@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 358CE37B400 for ; Thu, 5 Sep 2002 08:22:22 -0700 (PDT) Received: from mail.speakeasy.net (mail16.speakeasy.net [216.254.0.216]) by mx1.FreeBSD.org (Postfix) with ESMTP id C005743E75 for ; Thu, 5 Sep 2002 08:22:21 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: (qmail 3516 invoked from network); 5 Sep 2002 15:22:58 -0000 Received: from unknown (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) by mail16.speakeasy.net (qmail-ldap-1.03) with DES-CBC3-SHA encrypted SMTP for ; 5 Sep 2002 15:22:58 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.12.5/8.12.5) with ESMTP id g85FMJBv011339; Thu, 5 Sep 2002 11:22:20 -0400 (EDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.2 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <1031238584.2988.14.camel@jan-linux.lan> Date: Thu, 05 Sep 2002 11:22:19 -0400 (EDT) From: John Baldwin To: Jan Lentfer Subject: Re: alpha performance on -current Cc: freebsd-alpha@FreeBSD.org, Andrew Gallatin , ticso@cicely.de Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On 05-Sep-2002 Jan Lentfer wrote: > Am Don, 2002-09-05 um 16.51 schrieb Bernd Walter: >> On Thu, Sep 05, 2002 at 10:43:27AM -0400, John Baldwin wrote: >> > >> > On 05-Sep-2002 Andrew Gallatin wrote: >> > > I'm using the appended diff, which I think is what you're suggesting: >> > >> > I think what he is really suggesting is to remove the mb's from all the >> > atomic_foo ops that don't have _acq or _rel in them. The _acq and _rel >> > versions should be wrappers that add mb's. >> >> Exactly. > > OK, I didn't get anything from the first sentence until now. What the > heck are you guys talking about??? I mean it, could someone explain or > even better point me to some resources so I can actually understand what > you guys mean? This is about kernel design and memory managment, right? > Any recommended readings? > > Thanks a lot in advance, This is about implementing atomic operations on Alpha CPU's for use by the kernel. You can read the atomic(9) man page on current for more info about this. An atomic operation just guarantees that the operation it is performing is atomic, hence the fact that normal atomic_foo() oops don't need memory barriers. Only the versions of atomic ops (such as atomic_foo_acq() or atomic_foo_rel()) require that memory barriers be used to guarantee specific ordering restraints. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message