[whatwg] [Web workers] An attribute describing the "best" number of worker to invoke in a delegation use case

[David Bruant]

Boris Zbarsky a écrit :
> On 11/11/09 10:19 PM, David Bruant wrote:
>> This attribute have the following properties :
>> - It's only dependant on the hardware, the operating system and the
>> WebWorker implementation (thus, it is not dynamically computed by the
>> user agent at each call and two calls in the same
>> hardware//OS//WebWorker implementation have the same result).
>> - In the same running conditions (same memory available, same number of
>> process running concurrently...) running the "same algorithm" (an easy
>> delegation algorithm) has a significantly better performance with
>> (navigator.optimalWorkerNumber) workers than
>> (navigator.optimalWorkerNumber - 1) workers
>> - In the same running conditions, running the same algorithm has no
>> significantly better performance with (navigator.optimalWorkerNumber +1)
>> workers than (navigator.optimalWorkerNumber) workers
>
> I believe that these conditions are mutually contradictory.
>
> Indeed, condition 1 requires that optimalWorkerNumber be a constant
> independent of what the browser itself and other applications are doing.
=>  That is what I meant (and still mean)
> Condition 2 requires that running with navigator.optimalWorkerNumber
> has better performance than running with
> (navigator.optimalWorkerNumber - 1) workers.  In particular, it
> requires that this be the case even if there is already one worker
> doing something (due to condition 1).  This implies that performance
> with (navigator.optimalWorkerNumber+1) workers be better than that
> with navigator.optimalWorkerNumber workers, which directly violates
> condition 3.
=> You're perfectly right. I reformulate the definition of "running
conditions" (appearing in condition 2 and 3) as :
"same memory available, same number of process running concurrently, no
other worker running working on the same document".

David

>
> -Boris