> On 14 Oct 99, at 17:29, Lucas Wiman wrote:
> I'm most definitely _not_ Bill Gates's biggest fan, but I have to say
> that Windows NT _does_ multi-task pretty well. In fact, in a SMP
> environment, it's actually rather _more_ effective than linux, you
> can (but don't have to) force particular threads to run on a given
> processor. With luck, & provided there aren't _too_ many threads in
> the "need CPU cycles" queue, this can give you a significant
> performance boost, since the data you're working on might well be
> still available in the CPU cache, even if you've been timesliced or
> interrupted out since you fetched it - whereas pre-fetched data
> sitting in the cache of another processor is useless to you.
Linux is smarter -- it automaticaly gives preference for the last CPU
used, without any special settings. Sometimes, however, if for some
reason the kernel or other threads need that specific CPU, Linux will
move the process. You win.
Have you noticed what happens when you on Windows NT run one instence
of Prime95 on idle priority with affinity to one CPU and start a new
CPU-hogging program with normal priority and no processor affinity?
The other program will be on the first CPU 50% of the time and on the
other CPU the other 50% of the time. 25% of the time one CPU (the one
Prime95 isn't using) will be idle, while the other program is using
the CPU which Prime95's processor affinity is set to. That's how smart
the processor affinity of Windows NT is!
I agree that it should be possible to set the automatic "glue" stronger
on Linux for certain processes like mprime (without recompiling the
kernel) but I think Linux have a much better approach to this than NT.
--
Sturle URL: http://www.stud.ifi.uio.no/~sturles/ Er det m}ndag i dag?
~~~~~~ MMF: http://www.alladvantage.com/go.asp?refid=BUP399 - St. URLe
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