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Subject: Re: [Boost-users] boost asio synchronous vs asynchronous operations performance
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2014-03-28 06:26:39

On 28 Mar 2014 at 18:17, Gavin Lambert wrote:

> I had a case (with serial ports) where this locking latency was
> sufficiently high to be bothersome. I wrote an experimental lock-free
> reactor engine which appears to outperform Asio (at least on Windows) --
> but it's also much more limited and doesn't provide some of the same
> guarantees.
> For normal (particularly socket) usage it's probably not worth the hassle.

Windows has quite chunky thread switch times anyway, so as soon as
you need to wait on another thread via the kernel rather than CAS
lock you can forget about performance. Windows completion ports ought
to be completely user space when thread A posts work to thread B, but
any additional locking e.g. by ASIO can create enough stalls to send
completion ports to sleep in the kernel.

That said, it would be interesting to patch in TSX support to ASIO
instead of its mutex and see what happens.


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