From owner-freebsd-hackers Wed Mar 22 03:58:53 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id DAA02939 for hackers-outgoing; Wed, 22 Mar 1995 03:58:53 -0800 Received: from Root.COM (implode.Root.COM [198.145.90.1]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id DAA02933 for ; Wed, 22 Mar 1995 03:58:37 -0800 Received: from corbin.Root.COM (corbin.Root.COM [198.145.90.18]) by Root.COM (8.6.8/8.6.5) with ESMTP id DAA02688; Wed, 22 Mar 1995 03:57:44 -0800 Received: from localhost (localhost [127.0.0.1]) by corbin.Root.COM (8.6.11/8.6.5) with SMTP id DAA02482; Wed, 22 Mar 1995 03:57:43 -0800 Message-Id: <199503221157.DAA02482@corbin.Root.COM> X-Authentication-Warning: corbin.Root.COM: Host localhost didn't use HELO protocol To: Bruce Evans cc: freebsd-hackers@freefall.cdrom.com, kuku@gilberto.physik.rwth-aachen.de Subject: Re: Why IDE is bad In-reply-to: Your message of "Wed, 22 Mar 95 21:49:25 +1000." <199503221149.VAA12384@godzilla.zeta.org.au> From: David Greenman Reply-To: davidg@Root.COM Date: Wed, 22 Mar 1995 03:57:42 -0800 Sender: hackers-owner@FreeBSD.org Precedence: bulk >>>This might explain why my Intr time is so much lower than Poul's. >>>I have only 16MB, and don't use option BOUNCE_BUFFERS. The bcopy() >>>for bouncing is done in a call from biodone(). biodone() is called >>>from the interrupt handler, at least for the wd driver. > >> Bounce buffers are not used on wd-style drives. > >I just looked at wd.c because there's no direct call to biodone() in >bt742a.c. I think it gets called from the upper layers for scsi >drivers. It's called from sd.c and other places. Only B_BOUNCE buffers are freed in biodone. B_BOUNCE buffers are only created in vm_bounce_alloc(), and that is only called for bus mastering controllers that can't DMA above 16MB. -DG