Subject AW: [ib-support] SMP Problems with SS on Linux.
Author Christian G├╝tter
Hi Gerhardus,

AFAIK the Firebird engineers want to fix the
CPU affinity mask of Firebird so that the
server process only uses one CPU in a dual
CPU systems. Maybe they have already done this;
I heard that this fix should be implemented
in Firebird 1.0.

The problem (in very simple terms) is that FB/IB
runs on one CPU, Windows NT sees that the CPU is
busy and switches the server process to the second CPU.
Then the second CPU is busy and NT switches the server
process to the first CPU.
This behaviour continues and the server process remains
in this vicious circle and IB/FB gets slower than with
just one CPU because NT uses too much time switching
Fixing the affinity mask makes the server process stay
on one CPU.

AFAIK this problem occurs only with IB/FB in combination
with Windows NT 4/5, I haven't yet heard anything about

However, using Firebird, you should be safe, because the
affinity mask fix is/will be implemented in FB1 - I saw
the FB engineers discussing about it in the developer forum.

Perhaps one of them can clarify if the fix is already included
in the current build.



> -----Urspr├╝ngliche Nachricht-----
> Von: Gerhardus Geldenhuis [mailto:flooder@...]
> Gesendet: Montag, 29. Oktober 2001 13:40
> An:
> Betreff: [ib-support] SMP Problems with SS on Linux.
> Hi
> I know there is smp problems with superserver when running on
> windows is the
> same problem also occurring in the linux version of FB1.
> Is it an architecture problem of FB or of the os?
> Groete
> Gerhardus