[cairo] Re: On recovery from errors in cairo (was: cairo reset)

Kalle Vahlman kalle.vahlman at gmail.com
Mon Sep 25 23:29:39 PDT 2006


2006/9/25, Mike Emmel <mike.emmel at gmail.com>:
[snap]
> I've seen a lot of traffic on arm issues thats why I mentioned it.
> I just can't give numbers for the device I'm testing but most arm
> devices that use similar cpu's have about the same performance so
> it does not matter too much.

There's a lot of other variables that might kill the performance, for
example the 770 suffers a lot from slow userspace-to-framebuffer
transfers. My little (animated) cairo test mistakenly drew directly on
the X11 surface (ie. window) at first and was dog slow, even though
it's pretty simple in structure. When I converted it to use a
backbuffer and only transferring areas that changed, the speed grew
exponentially. Admittedly the backbuffering helped on my laptop too,
but far less in comparison.

> Maybe someone from intel will send him a xscale device...

We had a PXA290 at GUADEC and since our original demo ideas were
failing (due to driver problems), I ran the same Cairo demo there and
it was pretty good (this was before any of the real performance work
put to Cairo). The PXA290 is of course from the higher end and beats
770 by far in numbers so it wasn't a big surprise really.

But it was fun :)

-- 
Kalle Vahlman, zuh at iki.fi
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