Questions on the scheduler

[Kris Kennaway]

Oliver Herold wrote:
> Are there any numbers or technical papers? Just out of curiosity.

I ran a mysql benchmark against Dragonfly-current and FreeBSD 7 on an 
8-core machine (one of the workloads that FreeBSD now performs very well 
at) and found 0 scaling on dragonfly.  Their developers confirmed that 
the kernel is still entirely giant locked (as in FreeBSD 4) so no SMP 
performance benefits are possible.

The email thread is here:

   http://leaf.dragonflybsd.org/mailarchive/users/2007-05/msg00134.html

although the linked graph is offline.  The FreeBSD curve was essentially 
this one (FreeBSD has improved further since then):

   http://people.freebsd.org/~kris/scaling/scaling.png

with dragonfly a flat line at ~500 tps independent of load.

Kris