Re: Support for more than 256 CPU cores

Moin Rahman <[email protected]> Sun, 7 May 2023 23:51:34 +0200

Newsgroups	gmane.os.freebsd.architechture,gmane.os.freebsd.current
Message-ID	<[email protected]>


> On May 5, 2023, at 3:38 PM, Ed Maste <[email protected]> wrote:
> 
> FreeBSD supports up to 256 CPU cores in the default kernel configuration
> (on Tier-1 architectures).  Systems with more than 256 cores are
> available now, and will become increasingly common over FreeBSD 14’s
> lifetime.  The FreeBSD Foundation is supporting the effort to increase
> MAXCPU, and PR269572[1] is open to track tasks and changes.
> 
> As a project we have scalability work ahead of us to make best use of
> high core count machines, but at a minimum we should be able to boot a
> GENERIC kernel on such systems, and have an ABI for the FreeBSD 14
> release that supports such a configuration.
> 
> Some changes have already been committed in support of increased MAXCPU,
> including increasing MAX_APIC_ID (commit c8113dad7ed4) and a number of
> changes to reduce bloat (such as commits 42f722e721cd, e72f7ed43eef,
> 78cfa762ebf2 and 74ac712f72cf).
> 
> The next step is to increase the maximum cpuset size for userland.
> I have this change open in review D39941[2] and an exp-run request in
> PR271213[3].  Following that the kernel change for increasing MAXCPU is
> in D36838[4].
> 
> Additional work on bloat reduction will continue after this change, and
> looking forward FreeBSD is going to need ongoing effort from the
> community and the FreeBSD Foundation to continue improving scalability.
> 
> [1] https://bugs.freebsd.org/269572
> [2] https://reviews.freebsd.org/D39941
> [3] https://bugs.freebsd.org/271213
> [4] https://reviews.freebsd.org/D36838
> 

By any chance will this be merged into 13?

Kind regards,
Moin

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