From owner-freebsd-current@FreeBSD.ORG Sun Jul 22 00:12:45 2007 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 198B916A469 for ; Sun, 22 Jul 2007 00:12:45 +0000 (UTC) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (gate.funkthat.com [69.17.45.168]) by mx1.freebsd.org (Postfix) with ESMTP id 7A72013C46C for ; Sun, 22 Jul 2007 00:12:44 +0000 (UTC) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (iwf3ar2rciu244fc@localhost.funkthat.com [127.0.0.1]) by hydrogen.funkthat.com (8.13.6/8.13.3) with ESMTP id l6M0CgaY076966; Sat, 21 Jul 2007 17:12:42 -0700 (PDT) (envelope-from jmg@hydrogen.funkthat.com) Received: (from jmg@localhost) by hydrogen.funkthat.com (8.13.6/8.13.3/Submit) id l6M0Cffd076965; Sat, 21 Jul 2007 17:12:41 -0700 (PDT) (envelope-from jmg) Date: Sat, 21 Jul 2007 17:12:40 -0700 From: John-Mark Gurney To: Scott Long Message-ID: <20070722001240.GA1221@funkthat.com> Mail-Followup-To: Scott Long , David Christensen , pyunyh@gmail.com, current@freebsd.org References: <09BFF2FA5EAB4A45B6655E151BBDD9030483F161@NT-IRVA-0750.brcm.ad.broadcom.com> <20070718021839.GA37935@cdnetworks.co.kr> <09BFF2FA5EAB4A45B6655E151BBDD9030483F437@NT-IRVA-0750.brcm.ad.broadcom.com> <20070719002218.GA42405@cdnetworks.co.kr> <09BFF2FA5EAB4A45B6655E151BBDD9030483F5D2@NT-IRVA-0750.brcm.ad.broadcom.com> <469EEF02.7000804@samsco.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <469EEF02.7000804@samsco.org> User-Agent: Mutt/1.4.2.1i X-Operating-System: FreeBSD 5.4-RELEASE-p6 i386 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html Cc: pyunyh@gmail.com, David Christensen , current@freebsd.org Subject: Re: Getting/Forcing Greater than 4KB Buffer Allocations X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: John-Mark Gurney List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 22 Jul 2007 00:12:45 -0000 Scott Long wrote this message on Thu, Jul 19, 2007 at 00:56 -0400: > 1Gb and 10Gb adapters. The question I have is whether this new back-end > should be accessible directly through yet another bus_dmamap_load_foo > variant that the drivers need to know specifically about, or indirectly > and automatically via the existing bus_dmamap_load_foo variants. The > tradeoff is further API pollution vs the opportunity for even more > efficiency through no indirect function calls and no cache misses from > accessing the busdma tag. I don't like API pollution since it makes it > harder to maintain code, but the opportunity for the best performance > possible is also appealing. My vote would be to keep the existing api, and add a flag to the tag to select which backend to use... -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."