Erlang on the niagara

Stelianos G. Sfakianakis <>
Fri Jun 9 10:49:16 CEST 2006


On 6/8/06, Ulf Wiger <> wrote:
> Den 2006-06-08 19:01:23 skrev David Hopwood
> <>:
>
> > Joe Armstrong (AL/EAB) wrote:
> >> Why can't we speed up beyond a factor 7 - who knows? - at some stage
> >> things do get serialised, there is after all only one disk on the
> >> machine, and the SMP erlang has to serialise all disk I/O, even if the
> >> programs generating data run in parallel, [...]
> >
> > Do you mean that it does disk I/O in a single OS thread, or with a mutex
> > around the I/O code, or just that the I/O is serialized at the hardware
> > bus level?
>
> AFAIK, the whole I/O subsystem in OTP R11B is protected with a single
> big mutex.
>

Just to make sure that I understand this correctly, are you referring
only to the disk IO or
really to the *whole* IO system (including network)?

thanks
Stelios



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