linux-kernel - [RFC][PATCH 2/4] timer_list: Add the base offset so remaining nsecs are accurate for non monotonic timers

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Date:	Fri, 29 May 2015 13:24:26 -0700
From:	John Stultz <john.stultz@...aro.org>
To:	lkml <linux-kernel@...r.kernel.org>
Cc:	John Stultz <john.stultz@...aro.org>,
	Prarit Bhargava <prarit@...hat.com>,
	Daniel Bristot de Oliveira <bristot@...hat.com>,
	Richard Cochran <richardcochran@...il.com>,
	Jan Kara <jack@...e.cz>, Jiri Bohac <jbohac@...e.cz>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Shuah Khan <shuahkh@....samsung.com>
Subject: [RFC][PATCH 2/4] timer_list: Add the base offset so remaining nsecs are accurate for non monotonic timers

I noticed for non-monotonic timers in timer_list, some of the
output looked a little confusing.

For example:
 #1: <0000000000000000>, posix_timer_fn, S:01, hrtimer_start_range_ns, leap-a-day/2360
 # expires at 1434412800000000000-1434412800000000000 nsecs [in 1434410725062375469 to 1434410725062375469 nsecs]

You'll note the relative time till the expiration "[in xxx to
yyy nsecs]" is incorrect. This is because its printing the delta
between CLOCK_MONOTONIC time to the CLOCK_REALTIME expiration.

This patch fixes this issue by adding the clock offset to the
"now" time which we use to calculate the delta.

Cc: Prarit Bhargava <prarit@...hat.com>
Cc: Daniel Bristot de Oliveira <bristot@...hat.com>
Cc: Richard Cochran <richardcochran@...il.com>
Cc: Jan Kara <jack@...e.cz>
Cc: Jiri Bohac <jbohac@...e.cz>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Shuah Khan <shuahkh@....samsung.com>
Signed-off-by: John Stultz <john.stultz@...aro.org>
---
 kernel/time/timer_list.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index e878c2e..05a560f 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -132,7 +132,7 @@ print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 		   (unsigned long long) ktime_to_ns(base->offset));
 #endif
 	SEQ_printf(m,   "active timers:\n");
-	print_active_timers(m, base, now);
+	print_active_timers(m, base, now + ktime_to_ns(base->offset));
 }
 
 static void print_cpu(struct seq_file *m, int cpu, u64 now)
-- 
1.9.1

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