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authorPeter Zijlstra <peterz@infradead.org>2014-01-22 22:08:14 +0100
committerIngo Molnar <mingo@kernel.org>2014-01-23 14:48:36 +0100
commit5e3c1afd4587e70c201bf7224b51f747c9a3dfa8 (patch)
treed2608d056fbb0ccf2c47e7d3cc648b2fed0753e2 /arch/x86/kernel/tsc.c
parentd375b4e0fa3771343b370be0d876a1963c02e0a0 (diff)
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: 20d1c86a57762 ("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>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
-rw-r--r--arch/x86/kernel/tsc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index a3acbac2ee72..19e5adb49a27 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -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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