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From:	"Schmidt, Oliver" <oliv DOT schmidt AT sap DOT com>
To:	"cygwin AT cygwin DOT com" <cygwin AT cygwin DOT com>
Date:	Tue, 9 Mar 2010 11:08:22 +0100
Subject:	RE: Cygwin 1.7: Concurrency Issue with Shared State Initialization
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Hi Christopher,

Fist of all thanks for your immediate feedback :-)

>>    /* Initialize installation root dir. */
>>     if (!installation_root[0])
>>       init_installation_root ();

> I'll check in something tonight which attempts to solve this problem.

Thanks in advance.

> It's a somewhat tricky problem because adding a mutex here would slow
> down every invocation of a cygwin program and we don't want to add to
> the "Why is Cygwin so slow???" scenarios if we can help it.

I understand your concern for sure ;-)

Maybe that's the very thing you're thinking about but ... AFAIK a spinlock =
is the usual paradigm in scenarios where one doesn't anticipate contention =
but needs to be aware of it 'just in case'. With InterlockedCompareExchange=
() and Sleep() it should be quite simple to create one that's very efficien=
t in the usual scenario.

Regards, Oliver

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