Commit 5e3c1afd authored Jan 22, 2014 by Peter Zijlstra Committed by Ingo Molnar Jan 23, 2014

sched/x86/tsc: Initialize multiplier to 0



Since we keep the clock value linearly continuous on frequency change,
make sure the initial multiplier is 0, such that our initial value is 0.
Without this we compute the initial value at whatever the TSC has
managed to reach since power-on.

Reported-and-Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Fixes: 20d1c86a ("sched/clock, x86: Rewrite cyc2ns() to avoid the need to disable IRQs")
Cc: lenb@kernel.org
Cc: rjw@rjwysocki.net
Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: rui.zhang@intel.com
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith <bitbucket@online.de>
Cc: hpa@zytor.com
Cc: paulmck@linux.vnet.ibm.com
Cc: John Stultz <john.stultz@linaro.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: dyoung@redhat.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140123094804.GP30183@twins.programming.kicks-ass.net


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent d375b4e0

arch/x86/kernel/tsc.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -180,7 +180,7 @@ static void cyc2ns_write_end(int cpu, struct cyc2ns_data *data)

		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;

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