Subject Re: Multi core CPU's and FB 2.0 embedded
Author Adam
--- In, "Werner F. Bruhin"
<werner.bruhin@...> wrote:
> Hi Helen,
> Helen Borrie wrote:
> > At 01:40 AM 6/02/2007, you wrote:
> >> I didn't see a response to my earlier question, so I'll put the
> >> a bit different.
> >>
> >> Does one have to set the "CpuAffinityMask" setting in
firebird.conf for
> >> a Pentium D or other multi core CPU's when using FB 2.0 Embedded?
> >
> > It's set at CPU 0 (value 1) by default. Leave it as is unless you
> > want the single-CPU affinity to be to a different one.
> Is there any problem having that setting active (removing the comment
> marker) for a machine having a single CPU?

Unless you have a reason you want to change it, don't.

The defaults are in place largely to prevent the see saw effect of the
Windows scheduler bouncing the database engine process (for embedded
that is your process) between the two processors (or cores). If it
were a good idea to activate it regardless of CPU configuration, it
would be enabled by default.

Embedded is Superserver, so it can only run on a single core at a
time. Classic server is able to make use of multiple CPUs and multiple
cores, but lacks the shared cache which can be a slowdown.

It is hard to say where one model is good and the other is bad. For
our app, SS is usually better on up to 2 cores, even though it is only
making use of 1 of them. Four or more cores, CS is much better balanced.

You have to wait for Vulcan for this to be improved.