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Subject: Re: Cygwin multithreading performance
References: <CABPLASTtRK4mNxh0M_AnZgjJQ15kWPx+L=U=VCU3Wwi7jV_57A AT mail DOT gmail DOT com> <564E3017 DOT 90205 AT maxrnd DOT com> <CABPLASTLrH_udLuu2F-m5P6dkENW1Z4YHEudp4NG0-FGLJgPMg AT mail DOT gmail DOT com> <5650379B DOT 4030405 AT maxrnd DOT com> <20151121105301 DOT GE2755 AT calimero DOT vinschen DOT de> <5652C402 DOT 7040006 AT maxrnd DOT com> <24780-1448274431-7444 AT sneakemail DOT com>
To: cygwin AT cygwin DOT com
From: Mark Geisert <mark AT maxrnd DOT com>
Message-ID: <5653B52B.5000804@maxrnd.com>
Date: Mon, 23 Nov 2015 16:54:03 -0800
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John Hein wrote:
> Mark Geisert wrote at 23:45 -0800 on Nov 22, 2015:
>   > 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
>
> Someone recently mentioned on this list they were working on porting
> jemalloc.  That would be a good choice.

Indeed; thanks for the reminder.  Somehow I hadn't followed that thread.

..mark


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