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Re: Cygwin multithreading performance


Corinna Vinschen wrote:
On Nov 21 01:21, Mark Geisert wrote:
[...] so I wonder if there's
some unintentional serialization going on somewhere, but I don't know yet
how I could verify that theory.

If I'm allowed to make an educated guess, the big serializer in Cygwin
are probably the calls to malloc, calloc, realloc, free.  We desperately
need a new malloc implementation better suited to multi-threading.

That's very helpful to know. I'd want to first make sure the heavy lock activity I'm seeing in the traces really is due to malloc() and friends but I couldn't help a speculative search online for multithread-safe malloc(). These turned up: tcmalloc - part of google-perftools, requires libunwind, evidently not yet ported to Windows AFAICT,
    nedmalloc - http://www.nedprod.com/programs/portable/nedmalloc/
    ptmalloc - http://www.malloc.de/

The latter two are based on Doug Lea's dlmalloc which is also the basis of Cygwin's malloc() functions. As I understand it, ptmalloc in one form or another has been part of glibc on Linux for some time.

So there may be a solution in sight if we need to go that direction. Of course, SHTDI as usual :).

..mark

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