From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NuZW5-0006n1-FG for qemu-devel@nongnu.org; Wed, 24 Mar 2010 18:57:37 -0400 Received: from [140.186.70.92] (port=55548 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NuZW3-0006me-LE for qemu-devel@nongnu.org; Wed, 24 Mar 2010 18:57:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1NuZW2-0000OQ-1W for qemu-devel@nongnu.org; Wed, 24 Mar 2010 18:57:35 -0400 Received: from mail-gw0-f45.google.com ([74.125.83.45]:37273) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1NuZW1-0000OD-PX for qemu-devel@nongnu.org; Wed, 24 Mar 2010 18:57:33 -0400 Received: by gwb11 with SMTP id 11so2687281gwb.4 for ; Wed, 24 Mar 2010 15:57:30 -0700 (PDT) Message-ID: <4BAA98CD.4090900@codemonkey.ws> Date: Wed, 24 Mar 2010 17:57:17 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: Compile files only once: some planning References: <201003242247.53346.paul@codesourcery.com> In-Reply-To: <201003242247.53346.paul@codesourcery.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paul Brook Cc: Blue Swirl , qemu-devel@nongnu.org, Juan Quintela On 03/24/2010 05:47 PM, Paul Brook wrote: >> Actually, Anthony suggested at some point to just use 64 bits for >> TARGET_PHYS_ADDR_BITS and remove the need for hw32/64. >> >> I think that people emulationg 32bits on 32bits would suffer, but have >> no clue how much. Anthony, what was the idea? >> > Sacrificing runtime performance to avoid rebuilding a few files is not > acceptable. I consider the fact that TARGET_PHYS_ADDR_BITS is always 64 on 64- > bit hosts is a bug. It's just hard to fix, and probably even less of a > performance hit, so I haven't bothered yet. > It's a statement of correctness really. Devices should never deal with target_phys_addr_t's. The question is, should a pci_addr_t or a sysbus_addr_t be 64 bit or should it be 32-bit on 32-bit platforms. Honestly, I am extremely sceptical that there would be any measurable performance difference. Regards, Anthony Liguori > Paul > > >