A few notes on choosing between Go and D for a quick project

[Russel Winder via Digitalmars-d]

On Tue, 2015-03-17 at 22:49 +0000, deadalnix via Digitalmars-d wrote:
> On Tuesday, 17 March 2015 at 22:30:37 UTC, Andrei Alexandrescu 
> wrote:
> > On 3/17/15 1:50 PM, Bienlein wrote:
> >>
> >>> Go is only a CSP-like, it isn't CSP. cf Python-CSP and PyCSP, 
> >>> not to
> >>> mention JCSP and GPars.
> >>
> >> I'm not really sure whether this can be put exactly that way. 
> >> On a
> >> machine with 4 GB RAM you can spawn about 80.000 goroutines 
> >> (aka green
> >> threads). Let's say each threads calculates a large fibonacci 
> >> number. If
> >> the fibonacci calculation yields the processor frequently all 
> >> 80.000 run
> >> seamingly in parallel and return their result almost "at the 
> >> same time".
> >
> > How many physical threads would the 80K goroutines create? -- 
> > Andrei
> 
> The Go runtime manages this. About as many as there are CPU.

The Go runtime manages the threadpool and scheduling of kernel threads,
but the number of them remains a number specified manually unless you
want the default of 1.

Benchmarking generally reveals that optimal number of kernel threads in
a pool is number of CPUs ±1, it depends on the work and things like
cacheline misses, hyperthreads, etc., etc.

-- 
Russel.
=============================================================================
Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder at ekiga.net
41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel at winder.org.uk
London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder
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