Quoting Roland Dreier <[EMAIL PROTECTED]>: > However, this is not quite enough to make things work on > all powerpc systems, because the timebase does not necessarily run at > the same speed as the CPU. For example, on an IBM JS20 blade, > clock_test prints > > 1 sec = 6536.8 usec > 1 sec = 6537.05 usec > > (both as a 32-bit and 64-bit executable) because, as /proc/cpuinfo shows: > > processor : 0 > cpu : PPC970FX, altivec supported > clock : 2194.624509MHz > revision : 3.0 > > processor : 1 > cpu : PPC970FX, altivec supported > clock : 2194.624509MHz > revision : 3.0 > > timebase : 14318000 > machine : CHRP IBM,8842-P2C > > the timebase runs at about 14.3 MHz, or approx 153 times slower than > the CPU clock.
Right, the PPC book clearly says "Since the update frequency of the Time Base is implementation- dependent, the algorithm for converting the current value in the Time Base to time of day is also implementation-dependent." But I was hoping this would be 1:1 for most systems. > I'm not sure how you want to fix this in perftest. I plan on implementing a small program that will use msleep to measure the timebase rate. (Something like linear regression should do it). Tests will get a new option to pass in the timebase rate rather than guessing it from /proc/cpuinfo. -- MST _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
