forwarded message from Christian Tismer (fwd)

[Wiger Ulf]

Of course, it's always difficult to know exactly what's being
tested, and in this case also difficult to know what hardware
was used.

The erlang processor, ECOMP, could task switch in just a few
clock cycles, so it would have been up to it.

Regular erlang? Well, on my measly 400 MHz Pentium running
Windows 98, I measure about 800,000 context switches/s, which
does not compare (even though it probably suffices for most
applications). That's two erlang processes yielding to each other
in a tight loop.

Writing a simple call dispatcher, that calls a function object in each
loop (I suspect it's more similar to what Stackless Python does,
but don't really know anything about it), I register slightly over 2
million/s.

OK, cute, but what is the application?

/Uffe


From: "Bijan Parsia" <bparsia@REDACTED>

> Is Erlang up to this challenge?
>
> > Let me simply end this pamphlete with some simple sentences:
> > Stackless Python is more capable of tasklets switching than any
> > other light-weight threading software package.
> > If anyone disagrees, please give me a runnable counter-example.
> >
> > Here are some impressive site-specific time measurements, which
> > especially show, that 20.000.000 cframe tasklet switches per
> > second are really, really hard to beat.
> >
> > Pythonon Win32:
> >
> > D:\slpdev\src\2.2\src\Stackless\test>..\..\pcbuild\python taskspeed.py
> > 10000000 frame switches      took 3.83061 seconds, rate =    2610551/s
> > 10000000 frame softswitches  took 2.40112 seconds, rate =    4164718/s
> > 10000000 cfunction calls     took 2.13033 seconds, rate =    4694098/s
> > 10000000 cframe softswitches took 0.49296 seconds, rate =   20285627/s
> > 10000000 cframe switches     took 1.98907 seconds, rate =    5027486/s
> > 10000000 cframe 100 words    took 3.93737 seconds, rate =    2539768/s
> > The penalty per stack word is about 0.980 percent of raw switching.
> > Stack size of initial stub   = 14
> > Stack size of frame tasklet  = 58
> > Stack size of cframe tasklet = 35