From owner-freebsd-arch@FreeBSD.ORG Fri Jul 20 07:27:53 2012 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6EFBF106566B for ; Fri, 20 Jul 2012 07:27:53 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-pb0-f54.google.com (mail-pb0-f54.google.com [209.85.160.54]) by mx1.freebsd.org (Postfix) with ESMTP id 416BC8FC08 for ; Fri, 20 Jul 2012 07:27:53 +0000 (UTC) Received: by pbbro2 with SMTP id ro2so6192788pbb.13 for ; Fri, 20 Jul 2012 00:27:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=Hy3L2fsUMOG2m2/cypb1c2iqfhA5en/GIEsyyAo/gkg=; b=zLxNgZ5cdc+2ZzgDFFRba4HQ2uEun37Kkennw6BXAdMhuXHmEpSGg2N5ScRoL58zY7 n0hUUyQTw+JNl2X4l758li8qZSUsfMTYa2H3yy9dPR2rJrwkvfWiJckev7+ZFAE6W+yk sLK8mnigzwrKAmLWcw1QdbndSyICGbErLPUUuxPttPJ5rKSfN18e16AE21quWEsaUvkf 3IbA5qa6XGdX0zuRm898KwCltzINHQuwj0p6DWZfJlGakXSRmXxN8JJlRbNHBI9J2N6x vx9t63M4uYuGwyamNxc4iQNWxxPDIVvPX3NbZ6nKcD5BnkZnbFMOF5Wf/N0pmqO8fkhB /EJA== MIME-Version: 1.0 Received: by 10.68.201.9 with SMTP id jw9mr11583308pbc.28.1342769272790; Fri, 20 Jul 2012 00:27:52 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.68.191.138 with HTTP; Fri, 20 Jul 2012 00:27:52 -0700 (PDT) In-Reply-To: <500830D5.6000409@feral.com> References: <3CE55F29-A5B2-44A7-8854-1ED38BAE6F16@FreeBSD.org> <50075072.5050906@gmail.com> <500752CD.9030107@feral.com> <500830D5.6000409@feral.com> Date: Fri, 20 Jul 2012 00:27:52 -0700 X-Google-Sender-Auth: yKVL3C_SHdVi8L00GT1vruLBj-w Message-ID: From: Adrian Chadd To: mj@feral.com Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-arch@freebsd.org Subject: Re: aio in GENERIC? X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Jul 2012 07:27:53 -0000 On 19 July 2012 09:07, Matthew Jacob wrote: > On 7/19/2012 8:58 AM, Adrian Chadd wrote: >> >> .. the API supports the avoidance of copyin/copyout? >> >> > okay, I'll buy that, although I'm not certain of the utility in general of > that. > > The reason I asked was that I have rarely, if ever, run into an AIO > implementation that was more trouble than it was worth. It certainly has > caused major grief in FreeBSD when used with CAM target mode. Because the userland code was wrong, or because supporting it in the kernel for CAM target mode is hard? I used posix AIO for Squid servers. It dropped CPU use quite noticably. Adrian