Sergei Shtylyov wrote: > sched_clock() defined in arch/i386/kernel/timers/timer_tsc.c can > hardly provide 0-based time if it's using TSC (at least I can't see > where the TSC is cleared). Even if it's not using TSC, jiffies_64 is not > 0-based as we saw, and neither it's set to -300 secs because of the > double cast to ulong and then to u64 which should clear the high word. > Probably something somewhere clears TSC but I can see the related code > only in arch/i386/kernel/smpboot.c... I've worked a lot with the printk_times feature, and it's not unusual on many systems to see weird values before time_init(). On x86 with a TSC-based sched_clock() you may see values based on whatever the TSC happens to be after firmware initialization up until time_init(). Note that you can re-base the timings to an arbitrary printk line using scripts/show_delta. See http://tree.celinuxforum.org/CelfPubWiki/PrintkTimesSample2 ============================= Tim Bird Architecture Group Chair, CE Linux Forum Senior Staff Engineer, Sony Electronics =============================
