[Jun-ichi Odagiri]
"Michael Hohmuth" hohmuth@innocent.com writes:
Please note that currently L4Linux puts threads started by clone(...CLONE_VM...) into different L4 tasks. [...]
I've noticed this point. It implies that a TLB flush is required upon a "thread" switching ( L4 task switching ). It will take... how long? Maybe 10 microseconds or so, I guess.
Think close to 100 (?) cycles for the instruction itself and 25 cycles for each following TLB miss (numbers depending on CPU and memory access speeds of course). Assuming something above 100 TLB misses, you would then on a 500MHz processor get, as you say, an additional cost of about 10 microseconds. On a P4 these additional costs are even higher.
eSk