CPU core usage of SuperServer

[Mark Rotteveel]

Historically, SuperServer is said to be worse at using multiple CPU
cores for a single database compared to Classic.

In the Firebird 2.5 release notes, it says it is slightly improved: "A
slight improvement in scaling should be apparent for single database
usage on SMP hardware".

How I read this, is that it uses a single core for a specific database,
no matter the amount of connections to that database.

Is that still the current state, or were things further improved after
Firebird 2.5?

Mark
--
Mark Rotteveel

[Alex Peshkoff]

Mark, I've always thought that answer is obvious. Since v.3 firebird SS
is using many cores for multiple attachments to single database. What
exactly means 'many' here is hard to answer - that number is limited by
number of actively running attachments, various lock conflicts between
them, disk performance, etc. I can only say for sure that improvement of
scalability always had very high priority. And FB5 SS runs under high
load in average 2-4 times faster compared with 2.5 CS. Alexey has an
interesting related presentation, sorry - I have no link to put here.

[Dmitry Yemanov]

v3 offered full multi-core support, except that any particular user
connection cannot utilize more than one core.


Dmitry

[Mark Rotteveel]

Thanks.

The problem with things that are obvious, is that if they aren't
explicitly written down in things like release notes, then you end up
with guesses, rumours, and apocryphal stories that may be far off the
mark, or people repeating things that were written down in documentation
or books about very old versions which are no longer accurate.

And the last written down thing I could find was that quote from the
Firebird 2.5 release notes.

Mark
--
Mark Rotteveel

[Mark Rotteveel]

On 31/10/2024 10:16, 'Mark Rotteveel' via firebird-devel wrote:
> And the last written down thing I could find was that quote from the
> Firebird 2.5 release notes.

And as it turns out, the Firebird 3.0 Release Notes do mention it, just
not in the section I was expecting to find it:

"""
In Superserver mode, the engine now makes use of multiple CPUs and cores
when spawning connections.
"""

Mark
--
Mark Rotteveel