Dear co-developers, Several months ago I noticed that even if I have working DMA, R128PutImage still eats lots of CPU, up to 26%, depending on video size. Several weeks ago I complained about this already, at that time it seemed to be a problem with aviplay or SDL. But since then I was able to reproduce it also with mplayer with -vo xv.
The best problem description I can give you is this like this: when the player
is doing nothing for some time after returning from calling XvShmPutImage, top
shows X doesn't eat any CPU. However, if it DOES do something (e.g. if I run
a multithreaded player like aviplay or set high postprocessing level to
mplayer), suddenly X eats 26% CPU. Even worse, if I disable dri (so that DMA
isn't used for this function), it eats up to 50% !!!.
This must have been introduced roughly in November. I remember it worked
wonderfully right after Michel and I wrote the DMA patch in September, aviplay
was able to eat 99% and X ate nothing. I remember now this isn't a hardware
problem, I also had this before I upgraded the motherboard, just wasn't able
to reproduce it predictably (now I CAN reproduce it anytime).
You can reproduce it anytime as well, find a high quality divx and run a
player (aviplay or mplayer), and run top over ssh, or perhaps even in another
window. You'll notice that with no postprocessing and reasonably fast cpu (>
500MHz), everything is ok, but when you turn the postprocessing to the max, X
will eat horribly lot of CPU. Setting postprocessing is easy, in aviplay you
turn "autoquality" off in the config and while playing the file, right-click,
choose properties and slide the slider. With mplayer, use -pp 0 or -pp 4.
Zdenek's (aviplay maintainer) and my current theory is that calling the
XvShmPutImage returns before it is actually run. A player then does XSync, so
that I can actually see the picture appear on screen, and calling another X
function until it's finished causes X to "hang" and this "eats" CPU time.
Parameters to SDL_Init don't change anything and as I said, I am able to
reproduce it with plain XvShmPutImage as well.
This is most probably not XF86 related but specific to r128, because I don't
remember upgrading X in between. In my hunt to exterminate this problem I
upgraded to XF86 4.2.0 (I had cvs 4.1.99 or something like that 'till then),
and cvs gatos from about a week a go. This didn't change anything.
So, I'd be very happy if someone could tell me if Zdenek's and my assumption
is right (that XvShmPutImage on r128 returns immediately and this was
introduced around November last year), and how to fix it (or even perhaps fix
it himself/herself, though I'm confident with a little hint I can do it
myself).
Thank you for your attention,
Peter Surda (Shurdeek) <[EMAIL PROTECTED]>, ICQ 10236103, +436505122023
--
The best things in life are free, but the
expensive ones are still worth a look.
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