Re: Winsock select timeout

From:
"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nospam>
Newsgroups:
microsoft.public.vc.language
Date:
Wed, 17 Oct 2007 09:29:41 -0700
Message-ID:
<O9FosrNEIHA.536@TK2MSFTNGP06.phx.gbl>
The design sounds extremely inefficient, both in resources and CPU use.

You aren't getting any benefit using 100 threads on a single CPU.
I bet you could use an IO completion port with 2 threads and get much better
performance.
This would be an event-driven solution, as Scott suggested.

Mark

--
Mark Salsbery
Microsoft MVP - Visual C++

<vanisathish@gmail.com> wrote in message
news:1192630618.951354.298320@e34g2000pro.googlegroups.com...

Hi,

i'm communicating with more than 40 serial devices connected thru' an
serial hub. the pc has to communicate thru' UDP to the serial hub.

since the response is quite sensitve, ( the application has to timeout
within 100msec) we are using "select" call with timeout.

There are around 100 threads that are parallely polling all the 40
devices on the serial hub.

I noticed that the select call is timingout i.e. returning 0
eventhough there is socket in the buffer..does this mean that the
timer got expired when that thread is in the sleep state (i.e. some
other thread is running) and later when the thread resumes, it is just
returning the previous state...

I'm running this application on a 2.66G Pentium PC..will the context
switching be an issue at all here. i dont see this problem if the
number of threads is reduced...,meaning less context switching.

thanks

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