On 11/12/09 7:24 PM, David Bruant wrote:
=> I think it happens very often. While I'm writing this e-mail, "no process" is running. About fifty processes are runnable, but not running. They are passively waiting. My CPU is barely used.
Interesting. I have several browser processes using timeslices right now (the incessant XHR google apps tend to do, I think), plus at least two other things running that are fully using up one core and most of another, as I write this mail.
I don't see how a browser could return a single number that would "work" or both of us.
My point is that this number may be available very easily. For example, in my dual-core, Linux, Firefox 3.5, the number is 2.
OK, what about in Firefox 3.6? If your worker plans to not allocate many strings and the like, it's 2. Otherwise, it's 1 (because a good bit of gc finalization has been moved to a separate thread).
Why spare an information that can be useful and reliable (more than measurement at least !) ?
Because the information is _not_ reliable. The optimal number of concurrent threads of execution given a given fixed set of computation resources is heavily dependent on the behavior of the threads of execution and what else is using the computation resources...
Put another way, as a UA implementor I don't know what I'd make this attribute return without it being a bald-faced lie in pretty simple cases.
=> Yes and no. No one can know if they will be optimally used or not. What you are "garanteed" (quotes again) is that in "blank conditions", they will be optimally used (which is more or less the definition of this number).
See above; even in "blank conditions" this may well depend on the exact workload of your workers.
-Boris
