changelog
---------
v10 - v9
        - Added another patch to this series that removes dependency
          between KVM clock, and memblock allocator. The benefit is that
          all clocks can now be initialized even earlier.
v9 - v8
        - Addressed more comments from Dou Liyang

v8 - v7
        - Addressed comments from Dou Liyang:
        - Moved tsc_early_init() and tsc_early_fini() to be all inside
          tsc.c, and changed them to be static.
        - Removed warning when notsc parameter is used.
        - Merged with:
          https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git

v7 - v6
        - Removed tsc_disabled flag, now notsc is equivalent of
          tsc=unstable
        - Simplified changes to sched/clock.c, by removing the
          sched_clock_early() and friends as requested by Peter Zijlstra.
          We know always use sched_clock()
        - Modified x86 sched_clock() to return either early boot time or
          regular.
        - Added another example why ealry boot time is important

v5 - v6
        - Added a new patch:
                time: sync read_boot_clock64() with persistent clock
          Which fixes missing __init macro, and enabled time discrepancy
          fix that was noted by Thomas Gleixner
        - Split "x86/time: read_boot_clock64() implementation" into a
          separate patch

v4 - v5
        - Fix compiler warnings on systems with stable clocks.

v3 - v4
        - Fixed tsc_early_fini() call to be in the 2nd patch as reported
          by Dou Liyang
        - Improved comment before __use_sched_clock_early to explain why
          we need both booleans.
        - Simplified valid_clock logic in read_boot_clock64().

v2 - v3
        - Addressed comment from Thomas Gleixner
        - Timestamps are available a little later in boot but still much
          earlier than in mainline. This significantly simplified this
          work.

v1 - v2
        In patch "x86/tsc: tsc early":
        - added tsc_adjusted_early()
        - fixed 32-bit compile error use do_div()

Adding early boot time stamps support for x86 machines.
SPARC patches for early boot time stamps are already integrated into
mainline linux.

Sample output
-------------
Before:
https://paste.ubuntu.com/26133428/

After:
https://paste.ubuntu.com/26133523/

For exaples how early time stamps are used, see this work:
Example 1:
https://lwn.net/Articles/734374/
- Without early boot time stamps we would not know about the extra time
  that is spent zeroing struct pages early in boot even when deferred
  page initialization.

Example 2:
https://patchwork.kernel.org/patch/10021247/
- If early boot timestamps were available, the engineer who introduced
  this bug would have noticed the extra time that is spent early in boot.

Pavel Tatashin (7):
  x86/tsc: remove tsc_disabled flag
  time: sync read_boot_clock64() with persistent clock
  x86/time: read_boot_clock64() implementation
  sched: early boot clock
  x86/paravirt: add active_sched_clock to pv_time_ops
  x86/tsc: use tsc early
  kvm/x86: remove kvm memblock dependency

 arch/arm/kernel/time.c                |   2 +-
 arch/s390/kernel/time.c               |   2 +-
 arch/x86/include/asm/paravirt.h       |   2 +-
 arch/x86/include/asm/paravirt_types.h |   1 +
 arch/x86/kernel/kvm.c                 |   1 +
 arch/x86/kernel/kvmclock.c            |  64 +++----------------
 arch/x86/kernel/paravirt.c            |   1 +
 arch/x86/kernel/setup.c               |   7 +-
 arch/x86/kernel/time.c                |  30 +++++++++
 arch/x86/kernel/tsc.c                 | 117 ++++++++++++++++++++++++++++------
 arch/x86/xen/time.c                   |   7 +-
 include/linux/timekeeping.h           |   3 +-
 kernel/sched/clock.c                  |  10 ++-
 kernel/time/timekeeping.c             |   8 ++-
 14 files changed, 164 insertions(+), 91 deletions(-)

-- 
2.16.1

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