libpthread / mysql41-server

[Julian Elischer]

On Sun, 21 Mar 2004, Scott Long wrote:

> Daniel Eischen wrote:
> > 
> > 
> > Mysql uses scope system threads which are limited to
> > kern.threads.max_groups_per_proc.  System scope threads
> > seem to have unfair scheduling also.  I use SCHED_4BSD
> > and this patch to mysql40-server to make it use process
> > scope threads and it works much better:
> > 
> >   http://people.freebsd.org/~deischen/mysql40-server.diffs
> > 
> > I haven't made a patch to other versions of mysql, but I
> > have sent the maintainer the patch.
> > 
> 
> Having MySQL work 'out of the box' is a critical item for the success
> of FreeBSD 5.3 and beyond.  Should your patch be incorporated into the
> port?  What are the tradeoffs between system and process scope threads
> in this situation?  Since issues with system scope threads seem to come
> up alot, what will it take to make them no longer be a problem?


system scope threads use more resources
They are artificially limmited in the kernel to 50 per process.
I guess we should increase that to 500 or something.

heck I just committed that change....

ULE also doesn't treat KSE threaded processes well, and there is a 
patch floating around to fix that but no-one is willing to commit it to 
ULE and Jeff has not commented on it.

it is reported to make a BIG difference to KSE programs.