[Ecls-list] Latest changes

[Juan Jose Garcia-Ripoll]

On Sun, Mar 18, 2012 at 11:19 PM, Matthew Mondor
<mm_lists at pulsar-zone.net>wrote:

> When I had done the initial benchmarking, what seemed to be the problem
> was that a thread waiting for a lock wouldn't wake up as fast as
> previously when the lock became available.  The wakeup mechanism
> probably helps but it's plausible that threads waiting on a lock still
> don't wake up as fast as with the pthreads implementation, which would
> likely explain the difference.
>

I have changed the implementation using now a FIFO queue. The times seem to
improve a lot for short tests, going up to 731 connections / s or 1.4 ms /
connection on average. For longer tests it degrades a bit and goes up to
1.9 ms, which I attribute to consing.

The queue is based on a spinlock and I believe the FIFO character plus the
fact that the waiters spinlock with waiting times that are at most 0.1s
should provide enough of a balance not to make it too unfair. But to be
honest, I have not done any research on how to make this theoretically
sound.

As potential improvements I see:
* Changing the queue so that it does not cons (perhaps with a "next" field
in the process object itself)
* The queue has the format multiple produces - one consumer, meaning that
it can be implemented without a lock (just CAS).

Juanjo

-- 
Instituto de Física Fundamental, CSIC
c/ Serrano, 113b, Madrid 28006 (Spain)
http://juanjose.garciaripoll.googlepages.com
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