[cairo] multithreaded bug in cairo on call to cairo stroke?

cu cairouser at yahoo.com
Thu Dec 16 19:56:34 PST 2010

Is there a plan or an estimate as to when simpleops may become part of
official pixman/cairo release?

My application just recently started hitting the concurrency issue.
Until now while drawing was multithreaded, it was essentially completely
interlocked, i.e. pretty much serialized.  Now there are threads drawing
into separate surfaces, but using the same colors and this results in
occasional crash inside pixman - which sounds very much like the issue
discussed in this thread.

I tried the patch that removes pattern caching. It appears to work
(can't be sure as crashes are not consistent). However, it slows
rendering by about 1-3%. Not critical but it would be better if this was
not necessary.


Philippe Leroux wrote:
> ya pixman/simpleops is fine for me now
> out of curiosity
> so if i change the source to a random pattern just after i created the context 
> (in each threads)
> would that force cairo to use a seperate source for each thread? and be kind of 
> a workaround?
> because, i tried and it doesnt seems to work
> i also tested your second patch (and without pixman/simplops)
> works fine, with colors !
> thanks
> Philippe

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