Subject Re: [firebird-support] Dual Processor
Author Daniel Rail

At September 25, 2003, 07:30, rodbracher wrote:
> I have been finding/searching for articles on the use of dual
> processors and firebird. These all seem outdated - so I would like to
> confirm.

> FB SS Windows / Linux should not be used as the processor swap time
> is large.

Apparently, it's not as bad under Linux as it is under Windows.

> FB CS Windows / Linux there will be a performance gain.

Firebird CS is designed to run in an SMP/hyperthreaded environment.
Since each connection spawns a new process, and it's that process that
get attached to a specific CPU.

> If we are using SS we should use IBAffininty to restrict the server
> to one processor.

With FB 1.0 SS and FB 1.5 SS, there's a parameter in the configuration
file to set the CPU affinity. But, if your processors are
hyperthread CPUs, you might need to turn the hyperthreading off, some
negative reports have been received.

> We are using FB 1.0.3 - Fb 1.5 addresses a lot of the SS dual proc
> issues ?

FB 1.5 SS still doesn't address the SMP issue correctly, but it will
be properly implemented in FB 2.0.

> BTW - does anyone know of a good tool to measure cpu queue / loads
> etc - specifically with large query loads using FB ?

With FB 1.5 SS, you can fine tune the thread scheduler in a way that a
large query wouldn't slow down another user.

Best regards,
Daniel Rail
Senior System Engineer
ACCRA Group Inc. (
ACCRA Med Software Inc. (