From owner-freebsd-hackers Sun Dec 2 9:39:53 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from aslan.scsiguy.com (aslan.scsiguy.com [63.229.232.106]) by hub.freebsd.org (Postfix) with ESMTP id B8DFD37B416 for ; Sun, 2 Dec 2001 09:39:51 -0800 (PST) Received: from scsiguy.com (localhost [127.0.0.1]) by aslan.scsiguy.com (8.11.5/8.11.5) with ESMTP id fB2HdhY23671; Sun, 2 Dec 2001 10:39:43 -0700 (MST) (envelope-from gibbs@scsiguy.com) Message-Id: <200112021739.fB2HdhY23671@aslan.scsiguy.com> To: David Greenman Cc: rsharpe@ns.aus.com, Matthew Dillon , freebsd-hackers@FreeBSD.ORG Subject: Re: Patch #3 (TCP / Linux / Performance) In-Reply-To: Your message of "Sun, 02 Dec 2001 05:18:54 PST." <20011202051854.A7713@nexus.root.com> Date: Sun, 02 Dec 2001 10:39:43 -0700 From: "Justin T. Gibbs" Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG >>Does the FreeBSD tcp stack do zero copy (page flip the data to >>userspace)? In the localhost case, it seems like there are two copies >>to/from userspace there. > > It has the ability to do it via sendfile() and a few other mechanisms, but >not as a normal part of typical read()/write(). Ahh, but there are patches floating around that do support zero-copy. Just ask Ken Merry and Drew Gallatin. I don't think they've been integrated due to lack of testing time, but they've existed for 2 or so years now. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message