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Message-Id: <1503520884-99253-1-git-send-email-pasha.tatashin@oracle.com>
Date: Wed, 23 Aug 2017 16:41:22 -0400
From: Pavel Tatashin <pasha.tatashin@...cle.com>
To: pasha.tatashin@...cle.com, x86@...nel.org,
linux-kernel@...r.kernel.org, mingo@...hat.com,
peterz@...radead.org, tglx@...utronix.de, hpa@...or.com,
douly.fnst@...fujitsu.com
Subject: [PATCH v5 0/2] Early boot time stamps for x86
changelog
---------
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://hastebin.com/jadaqukubu.scala
After:
https://hastebin.com/nubipozacu.scala
As seen above, currently timestamps are available from around the time when
"Security Framework" is initialized. But, 26s already passed until we
reached to this point.
Pavel Tatashin (2):
sched/clock: interface to allow timestamps early in boot
x86/tsc: use tsc early
arch/x86/include/asm/tsc.h | 4 +++
arch/x86/kernel/setup.c | 10 +++++--
arch/x86/kernel/time.c | 24 +++++++++++++++++
arch/x86/kernel/tsc.c | 47 +++++++++++++++++++++++++++++++++
include/linux/sched/clock.h | 4 +++
kernel/sched/clock.c | 64 ++++++++++++++++++++++++++++++++++++++++++++-
6 files changed, 150 insertions(+), 3 deletions(-)
--
2.14.1
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