On Wed, Jan 22, 2014 at 10:17:40PM +0100, Markus Trippelsdorf wrote: > Yes. Thanks Peter. >
Ah much simpler patch that should have the same effect: --- Subject: sched/x86/tsc: Initialize multiplier to 0 From: Peter Zijlstra <[email protected]> Date: Wed, 22 Jan 2014 22:08:14 +0100 Since we keep the clock value linearly continuous on frequency change, make sure the initial multiplier is 0, such that out initial value is 0. Without this we compute the initial value at whatever the TSC has managed to reach since power-on. Fixes: 20d1c86a57762 ("sched/clock, x86: Rewrite cyc2ns() to avoid the need to disable IRQs") Cc: [email protected] Cc: [email protected] Cc: Eliezer Tamir <[email protected]> Cc: [email protected] Cc: [email protected] Cc: Mike Galbraith <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: [email protected] Cc: [email protected] Cc: Thomas Gleixner <[email protected]> Cc: John Stultz <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arjan van de Ven <[email protected]> Cc: Sasha Levin <[email protected]> Cc: [email protected] Reported-by: Markus Trippelsdorf <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> --- arch/x86/kernel/tsc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -180,7 +180,7 @@ static void cyc2ns_write_end(int cpu, st static void cyc2ns_data_init(struct cyc2ns_data *data) { - data->cyc2ns_mul = 1U << CYC2NS_SCALE_FACTOR; + data->cyc2ns_mul = 0; data->cyc2ns_shift = CYC2NS_SCALE_FACTOR; data->cyc2ns_offset = 0; data->__count = 0; -- 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/
