Cygwin multithreading performance

[Mark Geisert]

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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