On Sat, Aug 22, 2009 at 06:09:12PM +0200, Manuel Lauss wrote: > The loops_per_jiffy detection in generic calibrate_delay is a bit off > (by ~0.5% usually); calculate the correct value based on detected core > clock. BogoMIPS value will now reflect cpu core clock correctly. It think this is pretty much solving a non-problem. The BogoMIPS number should only be used for various delay functions and the only give a guarantee for a minimum delay but barely any promise about accuracy of the delay. Due to interrupts consuming some CPU time and potencially producing extra cache misses the measured BogoMIPS value is expected to be a bit lower than what a naive calculation based on the CPU clock is predicting; effects that not only impact the calculation of the BogoMIPS number but also delays based on the BogoMIPS number. Here's an even easier solution: #include <linux/jiffies.h> ... preset_lpj = <loops_per_jiffie_value>; Avoid the change to Kconfig that eventually will become messy if other systems continue along this line. Ralf
