Multiple Instances and Processor

Does anyone know how sql handles processor delegation when you install
multiple instances of sql?
For example:
Default installation will use up to 100% of the processor.
Default installation with 1 named instance will each take 50%.
Default installation with 2 named instances will each take 33.333%
Thanks,
Markeach instance will potentially schedule spids on each processor unless you
use affinity mask within each instance...
once a spid is released to a processor SQL doesn't have any control over
it's excution...
actually... SQL assigns spids to something called a user mode scheduler
which is affinitized to a processor and the UMS hands the spids off...
books like Inside SQL Server 2000 or Ken Henderson's new internals books
have great content on topics like that...
--
Brian Moran
Principal Mentor
Solid Quality Learning
SQL Server MVP
http://www.solidqualitylearning.com
"Mark Newton" <mark.newton@.bdsmarketing.com> wrote in message
news:v11svv82d84m8rvn1vaic6fskbn0jabfo8@.4ax.com...
> Does anyone know how sql handles processor delegation when you install
> multiple instances of sql?
> For example:
> Default installation will use up to 100% of the processor.
> Default installation with 1 named instance will each take 50%.
> Default installation with 2 named instances will each take 33.333%
> Thanks,
> Marksql