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Re: [Qemu-devel] qvm86, kqemu and video speed
From: |
Leonardo E. Reiter |
Subject: |
Re: [Qemu-devel] qvm86, kqemu and video speed |
Date: |
Wed, 13 Apr 2005 16:09:56 -0400 |
User-agent: |
Debian Thunderbird 1.0 (X11/20050116) |
Well the proof is in the pudding as they say. Running the display
adapter benchmark with the Fresh Diagnose program under Windows 2000,
inlining the glue functions actually slows some things down a slight
bit, while improving others by a small margin. Overall there is no
measurable performance gain when the glue functions are inlined. So I
suppose there is no sense in doing that.
Processors these days are so smart, that perhaps the inlining actually
causes cache optimization problems in some cases and has a negative
(instead of the expected positive) performance effect.
- Leo Reiter
Leonardo E. Reiter wrote:
3. I think a really simple optimization may be to inline the glue
functions in vga_template.h, cirrus_vga_rop.h, and cirrus_vga_rop2.h,
which is very trivial. We tried that a while back and it did improve
performance a bit - for instance, it shaved 1.5 seconds off the boot
time of a Windows 2000 session. Windows 2000 likes to display heavy
graphics, like marquees, etc., while booting in its status dialog boxes,
which is why the improvement was there I think. Maybe Fabrice or
someone else can comment as to the possible consequences, other than the
obvious code size increase of using inline functions (which is not much
in this case) of inlining those functions. We didn't notice anything
adverse, but perhaps we weren't looking closely enough :) We will keep
testing over here, and if all goes well, post a patch that does this
simple optimization. That is, unless anyone can chime in with a good
reason not to do this of course.
--
Leonardo E. Reiter
Vice President of Engineering
Win4Lin, Inc.
Virtual Computing from Desktop to Data Center
Main: +1 512 339 7979
Fax: +1 512 532 6501
http://www.win4lin.com
- Re: [Qemu-devel] qvm86, kqemu and video speed, (continued)
- Re: [Qemu-devel] qvm86, kqemu and video speed, Alex Beregszaszi, 2005/04/12
- Re: [Qemu-devel] qvm86, kqemu and video speed, Fabrice Bellard, 2005/04/12
- Re: [Qemu-devel] qvm86, kqemu and video speed, use . reply-to . address, 2005/04/12
- Re: [Qemu-devel] qvm86, kqemu and video speed, Struan Bartlett, 2005/04/13
- Re: [Qemu-devel] qvm86, kqemu and video speed, Hetz Ben Hamo, 2005/04/13
- Re: [Qemu-devel] qvm86, kqemu and video speed, Leonardo E. Reiter, 2005/04/13
- Re: [Qemu-devel] qvm86, kqemu and video speed,
Leonardo E. Reiter <=
- Re: [Qemu-devel] qvm86, kqemu and video speed, Thomas Steffen, 2005/04/14
- Re: [Qemu-devel] qvm86, kqemu and video speed, Oliver Gerlich, 2005/04/18
- Re: [Qemu-devel] qvm86, kqemu and video speed, emuls, 2005/04/19
Re: [Qemu-devel] qvm86, kqemu and video speed, Jim C. Brown, 2005/04/13