pthread switch (was Odd KSE panic)

[Andrew Gallatin]

Julian Elischer writes:
 > 
 > 
 > On Tue, 6 Jul 2004, Andrew Gallatin wrote:
 > 
 > > 
 > > FWIW, inserting a pthread_yield() just before the ioctl call in the
 > > worker thread speeds things up quite a bit (100us -> 73us) in
 > > combination with kern.threads.virtual_cpu=1.
 > 
 > what about with kern.threads.virtual_cpu untouched?
 > and what about with the hlt sysctl?


kern.threads.virtual_cpu=2
machdep.cpu_idle_hlt=1

no yeild        123.6us
yeild           116.8us

kern.threads.virtual_cpu=2
machdep.cpu_idle_hlt=0
no yield        111.9
yield		112.9

kern.threads.virtual_cpu=1
machdep.cpu_idle_hlt=1
no yeild        100.8
yeild            75.0

kern.threads.virtual_cpu=1
machdep.cpu_idle_hlt=0
no yield         93.9
ield             67.9


 > does your worker thread loop to check if there is more work before
 > waiting to be notified?

Yes.  He takes a mutex, loops over all completed events, sending
pthread_signals as required, then releases the mutex and sleeps via
an ioctl.

Drew