(I've seen as much as 8 seconds) when switching between cpus. As each cpu comes up, early_init_intel() will currently set the sched_clock_stable flag true. When mark_tsc_unstable() runs, it clears the flag, but this only occurs once (the first time a cpu comes up whose TSC is not synchronized with cpu 0). After this, early_init_intel() will set the flag again as the next cpu comes up. Only set sched_clock_stable if tsc has not been marked unstable. Signed-off-by: Dimitri Sivanich Acked-by: Venkatesh Pallipadi Acked-by: Peter Zijlstra LKML-Reference: <20100301174815.GC8224@sgi.com> Signed-off-by: Ingo Molnar "1|@•1x