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From: Paul Brook <paul@codesourcery.com>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] Re: Qemu 2D performance plunges below acceptable levels
Date: Fri, 20 Feb 2009 17:16:01 +0000	[thread overview]
Message-ID: <200902201716.02074.paul@codesourcery.com> (raw)
In-Reply-To: <499EE1FD.50704@eu.citrix.com>

> Also I don't how to explain the fact that SDL_Flip is faster than
> SDL_UpdateRect on MacOSX according to malc: the same libsdl macosx faq I
>  linked before claims that SDL_DOUBLEBUF is not even supported on MacOsX.

I guess it's possible that under a sufficiently lame implementation a partial 
update could be slower than an update of the whole screen. e.g. if your 
accelerated blit routines isn't capable of copying rectangular regions you 
have to do the partial update a line at a time, whereas a full update is a 
single blit operation. Seems a fairly unlikely corner case though, especially 
as we tend to update a whole number of lines.

Paul

  reply	other threads:[~2009-02-20 17:16 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-15 13:10 [Qemu-devel] Qemu 2D performance plunges below acceptable levels Alexey Eremenko
2009-02-15 17:11 ` [Qemu-devel] " Alexey Eremenko
2009-02-16 10:31   ` Stefano Stabellini
2009-02-16 11:47     ` Avi Kivity
2009-02-16 16:15       ` Stefano Stabellini
2009-02-16 16:36         ` Avi Kivity
2009-02-17 17:48         ` Avi Kivity
2009-02-17 19:00           ` Stefano Stabellini
2009-02-18  8:46             ` Alexey Eremenko
2009-02-18  9:33               ` malc
2009-02-18 10:48                 ` Stefano Stabellini
2009-02-18 11:17                   ` malc
2009-02-18 11:27                     ` Alexey Eremenko
2009-02-18 11:32                       ` malc
2009-02-18 12:12                     ` Stefano Stabellini
2009-02-18 18:51                       ` malc
2009-02-19 15:14                       ` malc
2009-02-20 16:37                         ` Stefano Stabellini
2009-02-20 16:52                           ` Paul Brook
2009-02-20 17:01                             ` Stefano Stabellini
2009-02-20 17:16                               ` Paul Brook [this message]
2009-02-21  4:02                               ` malc
2009-02-23  3:06                                 ` Stefano Stabellini
2009-02-23  6:43                                   ` malc
2009-02-20 17:17                             ` Laurent Desnogues
2009-02-18 10:43               ` Stefano Stabellini

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