[okl4-developer] Fast address-space switching on GUMSTIX?

[xi yang]

Hi folks:

I write a test, running two thread in two different address space,
each thread execute
while(1){
  print the timestamp of performance counter of xscale
  set counter of xscale to 0
  L4_Yield()
}
It shows that the cost of switching  to other address space is about
4000 cycles and 7 TLB miss.
 I find that after each time of address space switching, when new
thread begin execute in user level, a exception occurs, which is a
domain exception and then kernel flush the TLB and cache.

Dose Fast address space switching works on gumstix(Xscale) ?  I have
ported RTEMS on L4, when the interrupt handler and RTEMS in the same
PD, the number of interrupt latency is very good!(1000-3000)Cycles,
but if interrupt handler in another address space, the latency will be
10 times than same PD. The cost is from flushing TLB and TLB miss.
Hence reduce the number of times of flushing TLB is important for this
project.
I use OKL41.5.2.

Regards.