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| author |   Peter Zijlstra <peterz@infradead.org> | 2014-01-22 22:08:14 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2014-01-23 14:48:36 +0100 |
| commit | 5e3c1afd4587e70c201bf7224b51f747c9a3dfa8 (patch) | |
| tree | d2608d056fbb0ccf2c47e7d3cc648b2fed0753e2 /arch/x86 | |
| parent | sched/clock: Fixup early initialization (diff) | |
| download | linux-dev-5e3c1afd4587e70c201bf7224b51f747c9a3dfa8.tar.xz linux-dev-5e3c1afd4587e70c201bf7224b51f747c9a3dfa8.zip | |
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')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 2 |
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; |