Using gtod() can amount to a substantial disturbance of the thing to be measured. Using rdtsc, things seem reliable so far, and we have an FPGA (accessed through the PCI bus) that has been programmed to give access to an 8MHz clock and we do some checks against that.
Same here. gettimeofday() is way too slow (dual Opteron box) for the frequency I need to call it at. HPET is not available. But TSC is doing just fine. Plus in my case I don't care about sync between CPUs (thread that uses TSC is running on the isolated CPU) and I have external time source that takes care of the drift. So please no trapping of the RDTSC. Making it clear (bold kernel message during boot :-) that TSC(s) are not in sync or unstable (from GTOD point of view) is of course perfectly fine. Thanx Max - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/