Interesting benchmark performance (was RE: Pitiful benchmark perf ormance)

Ulf Wiger etxuwig@REDACTED
Fri Jun 15 09:29:30 CEST 2001

This was interesting.

Erlang strikes me as more and more human.  ;)
I seem to function in the same way: when I have lots to do, I
become more efficient; when I have little to do, I become very

Seriously, Erlang *has been* highly optimized for the very type
of systems where there are lots of things going on at once. This
reflects on the I/O, for example, where Erlang tries to handle up
to hundreds of active I/O ports fairly, rather than handling only
one extremely well.

Perhaps for example the ETOS implementation could focus more
squarely on efficiently running applications with much less
concurrency? It seems to be very good at that already.


On Thu, 14 Jun 2001, Sean Hinde wrote:

>> What would happen if you e.g. change INPUT_REDUCTIONS in erl_vm.h
>> from (2* CONTEXT_REDS) to CONTEXT_REDS, doubling the I/O poll
>> frequency?  (CONTEXT_REDS is set to 1000)
>> If basically all that happens in the erlang vm is that some 
>> process is waiting for I/O, ports may not be polled with any
>> predictably high frequency (then again, this is only guessing
>> wildly. Perhaps it effectively gives the ports even higher
>> priority...)
>I didn't try this but did get the benchmark to spawn an additional process
>to do this:
>busy() ->
>  busy().
>The time to complete the benchmark came down to:
>real    0m34.032s
>user    0m22.190s
>sys     0m11.640s
>real    0m45.845s
>user    0m32.910s
>sys     0m11.790s
>while also completing some huge amount of additional work..
>We have a number of machines working as pure mnesia servers running small
>transactions - pretty much exactly what this benchmark is simulating. I will
>do some more testing but it looks like in this sort of OLTP type
>applications where there is little else going on in the emulator except -
>read message from tcp/ip, do small work, wait for next message there might
>be a useful boost in throughput available.
>More thoughts anyone?
>- Sean
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Ulf Wiger                                    tfn: +46  8 719 81 95
Senior System Architect                      mob: +46 70 519 81 95
Strategic Product & System Management    ATM Multiservice Networks
Data Backbone & Optical Services Division      Ericsson Telecom AB

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