I enabled the printing of all values. There is bigger gap between two reading, it seems isync bring to performance drop.
Could you elaborate what does "closer that 64 tick together" mean?

You can see the attached log, the 0x40 is not always set.

Thanks
Gino

2010/3/26 Segher Boessenkool <segher@kernel.crashing.org>
> After trying the new code with "isync" and unsigned long long convertion,
> this problem doesn't happen(I tested for several minutes).

Do you now ever get two consecutive time readings that are closer
that 64 tick together?  If not, it's simply hiding the problem.

Do you ever now read a value that does not have the bit with value
0x40 set?


Segher