Re: Win32 shared memory speed - Mailing list pgsql-hackers

From James Mansion
Subject Re: Win32 shared memory speed
Date
Msg-id 4736EDB0.90305@mansionfamily.plus.com
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In response to Re: Win32 shared memory speed  ("Magnus Hagander" <magnus@hagander.net>)
Responses Re: Win32 shared memory speed  (Magnus Hagander <magnus@hagander.net>)
List pgsql-hackers
Magnus Hagander wrote:
> IIRC, there hasn't been any direct benchmark for it (though I've wanted to do that but had no time), but it's been
theolnly real explanation put forward for the behaviour we've seen. And it does make sense given the thread-centric
viewof the windows mm.
 
>
> /Magnus 
>   
How is it supposed to be slow, once its mapped into your process?  
There's no OS interaction at all then.

If you are suggesting that the inter-process synch objects are slow, 
then that may be so: just use interlocked
increment and a spin lock in place of a mutex and use an associated 
event to wake up if necessary.

You dont have to use a named kernel mutex, though it may be handy while 
setting up the shared memory.

If you are repeatedly changing the mappings - well, that may be 
something that needs optimisation.


James



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