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From:  John Stultz <>
To:  LKML <>
Subject:  [PATCH 0/2] [RFC] Introduce CLOCK_BOOTTIME
Date:  Wed, 15 Dec 2010 16:40:46 -0800
Message-ID:  <>
Cc:  John Stultz <>, Jamie Lokier <>, Thomas Gleixner <>, Alexander Shishkin <>, =?UTF-8?q?Arve=20Hj=F8nnev=E5g?= <>
Archive-link:  Article

After some discussions with Jamie Lokier about some of the 
drawbacks of CLOCK_MONOTONIC not incrementing during suspend
I wanted to see if we couldn't provide a new clockid that would 
allow applications that wanted to be aware of time passing during
suspend without having to deal with the inconsistencies of 
CLOCK_REALTIME caused by calls to settimeofday.

So this patchset introduces CLOCK_BOOTTIME, which is identical
to CLOCK_MONOTONIC, but includes any time spent in suspend.

This is just my initial stab at this, so I'd appreciate any comments
or thougths on these patches.

Jamie: On platforms that don't implement read_persistent_clock,
your issue would still be present, but fixing that is on my list.
Other then that issue, does this seem to address your concern?

Thomas: Let me know if the hrtimer_base indirection is too 
gross. It just seemed silly to create 5 empty bases so we could
have an exact match between the clockids and the bases.

Arve: I believe CLOCK_BOOTTIME would be sufficient for what
Android is using as elapsedRealtime() or 
ANDROID_ALARM_ELAPSED_REALTIME. If not please let me know why.


CC: Jamie Lokier <>
CC: Thomas Gleixner <>
CC: Alexander Shishkin <>
CC: Arve Hj??<>

John Stultz (2):
  hrtimers: extend hrtimer base code to handle more then 2 clockids
  hrtimers: Add CLOCK_BOOTTIME clockid, hrtimerbase and posix interface

 include/linux/hrtimer.h   |   22 ++++++++++++-
 include/linux/time.h      |    4 ++
 kernel/hrtimer.c          |   44 ++++++++++++++++---------
 kernel/posix-timers.c     |   16 ++++++++-
 kernel/time/timekeeping.c |   79 ++++++++++++++++++++++++++++++++++++++++++++-
 5 files changed, 146 insertions(+), 19 deletions(-)


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