提交 069569e0 编写于 作者: I Ingo Molnar

time: ntp: simplify ntp_tick_adj calculations

Impact: micro-optimization

Convert the (internal) ntp_tick_adj value we store from unscaled
units to scaled units. This is a constant that we never modify,
so scaling it up once during bootup is enough - we dont have to
do it for every adjustment step.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
上级 2b9d1496
......@@ -71,7 +71,8 @@ static long time_reftime;
long time_adjust;
static long ntp_tick_adj;
/* constant (boot-param configurable) NTP tick adjustment (upscaled) */
static s64 ntp_tick_adj;
/*
* NTP methods:
......@@ -89,7 +90,7 @@ static void ntp_update_frequency(void)
second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
<< NTP_SCALE_SHIFT;
second_length += (s64)ntp_tick_adj << NTP_SCALE_SHIFT;
second_length += ntp_tick_adj;
second_length += time_freq;
tick_nsec = div_u64(second_length, HZ) >> NTP_SCALE_SHIFT;
......@@ -540,6 +541,8 @@ int do_adjtimex(struct timex *txc)
static int __init ntp_tick_adj_setup(char *str)
{
ntp_tick_adj = simple_strtol(str, NULL, 0);
ntp_tick_adj <<= NTP_SCALE_SHIFT;
return 1;
}
......
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