Timur Tabi writes: > Can someone explain CLOCK_TICK_RATE to me? It's defined in > arch/powerpc/include/asm/timex.h as such: > > #define CLOCK_TICK_RATE 1024000 /* Underlying HZ */ > > Every architecture defines this, but some use the better comment > "Underlying frequency of the HZ timer". > > My question is: why is this a constant? Shouldn't it be a variable, > perhaps something that is based on tb_ticks_per_usec?
It's used essentially for making small adjustments to ACTHZ and TICK_NSEC in include/linux/jiffies.h. The value was chosen so that ACTHZ == HZ and TICK_NSEC = 1e9 for all common HZ values, since we can't say at compile time what the decrementer frequency will be. I believe it's all pretty moot since we changed over to using the generic time framework anyway. Paul. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev