Vladimir Dergachev wrote:
>>Using pipes or shared memory to pass things around to other processes on
>>the same box is very fast indeed, but if we base our design around
>>something like RServe which uses TCP it could be significantly slower.
>>Our R-based system will be running scripts in response to high-volume
>>real-time stock exchange data, so we expect lots of calls to many tiny
>>functions indeed.
>
> Very interesting :)
>
> If you are running RServe on the other box you will need to send data over
> ethernet anyway (and will probably use TCP). If it is on the same box and you
> use "localhost" the packets will go over loopback - which would be
> significantly faster.
I'd like to do as little IO as possible, so I'm looking at using a
single, very powerfull box and keep everything local.
> At some point (years ago) there was even an argument on some mailiing list
> (xfree86-devel ?) about whether Xserver should support shared memory as unix
> socket was "fast enough" - with the other side arguing that when you pass
> megabyte images around (as in DVD playback) there is non-negligible overhead.
We're currently doing performance tests with the RServe-approach where
we measure the actual evaluation time of a function. I'm interested in
the evaluation-time versus overhead ratio. Loopback TCP might work as
long as this ratio is sufficiently high.
Erik
--
Practice is the best of all instructors.
-- Publilius
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