Re: [Boost-users] [Serialization] Speedding up client-servercommunication

Subject: Re: [Boost-users] [Serialization] Speedding up client-servercommunication
From: Robert Ramey (ramey_at_[hidden])
Date: 2010-02-05 01:10:34

Ruediger Berlich wrote:
> Hi there,
>
> I am in the process of speeding up communication between a server and
> its clients. Communication involves serialized class data. Messages
> can be as large as 100 kilobytes.
>
> I have done some measurements which have shown that, in a cluster with
> Gigabit networking, most overhead of the parallelisation seems to
> come from the Broker infrastructure and the process of
> (de-)serialization. Network latency and/or bandwidth seems to play
> only a minor role in this environment.
>
> Hence, apart from optimizing my broker, I'm looking for ways to
> optimize the serialization process, as used in my application. As
> messages are discarded as soon as they reach the recipient, versions
> of serialized data do not play an important role.
>
> Apart from decreasing the frequency and size of data exchanges and
> using binary transfers in a homogeneous environment, another way of
> speeding up the application seems to be the "Class Information"
> section discussed e.g. in
> http://www.boost.org/doc/libs/1_41_0/libs/serialization/doc/special.html

If speed is paramount and you don't need versioning, you can mark your
classes accordingly.  If you're using this for passing data over the network
and you have control over both ends, versioning should not be necessary.
That could make a huge difference.  Also if you turn off tracking, that
could make big difference as well.

> Also, BOOST_IS_BITWISE_SERIALIZABLE(my_class) might help. One
> question I have about this is whether a std::vector<POD> would be
> accessible to this optimization ? I use quite a few of them.

collections of types marked with BOOST_IS_BITWISE_SERIALIZABLE(my_class)
serialized with the binary_?archive should be pretty much as fast as any 
other
method. On my system when I disassemble these types, one can verify
that it boils down the minimum code possible- at least with my MSVC 
compiler.

One large bottle neck I've found is in the usage of standard stream buffer.
Replacing this with a custom implemenation might help.

>
> Do you have further suggestions for ways of influencing the
> Boost.Serialization library ?

see all of the above.  Carefully read the serialization traits section
of the documentation.  I should say that I'm very skeptical of attempts
to make such improvements without subjecting one's own use
cases to a profiler.  The library has a section "performance" which
has a few tests which work with the bjam build/test system.  You
should add your own tests here and run them before doing too much.

>
> Thanks and Best Regards,
> Ruediger

Robert Ramey