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[POWERPC] Modify sched_clock() to make CONFIG_PRINTK_TIME more sane

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When booting a current kernel with CONFIG_PRINTK_TIME enabled you'll
see messages like:

[    0.000000] time_init: decrementer frequency = 188.044000 MHz
[    0.000000] time_init: processor frequency   = 1504.352000 MHz
[3712914.436297] Console: colour dummy device 80x25

This cause by the initialisation of tb_to_ns_scale in time_init(), suddenly the
multiplication in sched_clock() now does something :).  This patch modifies
sched_clock() to report the offset since the machine booted so the same
printk's now look like:

[    0.000000] time_init: decrementer frequency = 188.044000 MHz
[    0.000000] time_init: processor frequency   = 1504.352000 MHz
[    0.000135] Console: colour dummy device 80x25

Effectivly including the uptime in printk()s.

This patch makes tb_to_ns_scale and tb_to_ns_shift static and
read_mostly for good measure.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Tony Breeds 2007-07-04 14:04:31 +10:00 committed by Paul Mackerras
parent 4bb092811c
commit fc9069fe56
1 changed files with 6 additions and 3 deletions
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9
arch/powerpc/kernel/time.c
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@ -112,8 +112,9 @@ u64 ticklen_to_xs; /* 0.64 fraction */
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL_GPL(rtc_lock);
u64 tb_to_ns_scale;
unsigned tb_to_ns_shift;
static u64 tb_to_ns_scale __read_mostly;
static unsigned tb_to_ns_shift __read_mostly;
static unsigned long boot_tb __read_mostly;
struct gettimeofday_struct do_gtod;
@ -755,7 +756,7 @@ unsigned long long sched_clock(void)
{
if (__USE_RTC())
return get_rtc();
return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift;
return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
}
int do_settimeofday(struct timespec *tv)
@ -974,6 +975,8 @@ void __init time_init(void)
}
tb_to_ns_scale = scale;
tb_to_ns_shift = shift;
/* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
boot_tb = get_tb();
tm = get_boot_time();