From: tony@bakeyournoodle•com (Tony Breeds)
To: Olof Johansson <olof@lixom•net>
Cc: LinuxPPC-dev <linuxppc-dev@ozlabs•org>
Subject: Re: [PATCH/RFC] Modify sched_clock() to make CONFIG_PRINTK_TIME more sane.
Date: Wed, 20 Jun 2007 12:02:11 +1000 [thread overview]
Message-ID: <20070620020211.GO9768@bakeyournoodle.com> (raw)
In-Reply-To: <20070619145356.GA20382@lixom.net>
On Tue, Jun 19, 2007 at 09:53:56AM -0500, Olof Johansson wrote:
> It only seems to be used in this file, so it can be static, right?
True, I was following suit with tb_to_ns_scale, tb_to_ns_shift which
could also be static.
Here's an updated patch that makes them all static and updates the
commit message as well.
From: Tony Breeds <tony@bakeyournoodle•com>
Modify sched_clock() to make CONFIG_PRINTK_TIME more sane.
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
Effectively including the uptime in printk()s.
Also this patch makes tb_to_ns_scale and tb_to_ns_shift static for good
measure.
Signed-off-by: Tony Breeds <tony@bakeyournoodle•com>
---
There looks to be other variables that could be made static, I think
that's a job for another day though.
arch/powerpc/kernel/time.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
Index: working/arch/powerpc/kernel/time.c
===================================================================
--- working.orig/arch/powerpc/kernel/time.c
+++ working/arch/powerpc/kernel/time.c
@@ -113,8 +113,9 @@ 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;
+static unsigned tb_to_ns_shift;
+static unsigned long boot_tb;
struct gettimeofday_struct do_gtod;
@@ -735,7 +736,7 @@ 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)
@@ -960,6 +961,8 @@ 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();
Yours Tony
linux.conf.au http://linux.conf.au/ || http://lca2008.linux.org.au/
Jan 28 - Feb 02 2008 The Australian Linux Technical Conference!
next prev parent reply other threads:[~2007-06-20 2:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-19 6:35 [PATCH/RFC] Modify sched_clock() to make CONFIG_PRINTK_TIME more sane Tony Breeds
2007-06-19 6:43 ` Segher Boessenkool
2007-06-19 14:53 ` Olof Johansson
2007-06-20 2:02 ` Tony Breeds [this message]
2007-06-20 2:27 ` Olof Johansson
2007-06-20 3:13 ` [PATCH/RFC] Make certain timekeeping variables __read_mostly Tony Breeds
2007-06-20 7:41 ` Geert Uytterhoeven
2007-06-21 4:41 ` Tony Breeds
2007-06-20 7:37 ` [PATCH/RFC] Modify sched_clock() to make CONFIG_PRINTK_TIME more sane Geert Uytterhoeven
2007-06-21 4:29 ` Tony Breeds
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