[PATCH v3 0/3] Early boot time stamps for arm64
From: Pavel Tatashin
Date: Wed Dec 26 2018 - 11:45:31 EST
v2 - v3
Addressed comments from Will Deacon: split into three
patches, removed hardcoded assumption from vdso, don't
assign arch_timer_read_counter during early boot.
v1 - v2
Addressed comments from Marc Zyngier
I made early boot time stamps available for SPARC and X86.
As discussed at plumbers, I would like to add the same for arm64. The
implementation does not have to be perfect, and should work only when early
clock is easy to determine. arm64 defines a clock register, and thus makes
it easy, but on some platforms frequency register is broken, so if it is
not known, simply don't initialize clock early.
As seen from the above with base smp_init is finished after 0.47s:
[ 0.464585] SMP: Total of 8 processors activated.
But, in reality, 3.2s is missing which is a quiet long considering this is
only 60G domain.
Pavel Tatashin (3):
arm_arch_timer: add macro for timer nbits
arm64: vdso: Use ARCH_TIMER_NBITS to calculate mask
arm64: Early boot time stamps
arch/arm64/kernel/asm-offsets.c | 1 +
arch/arm64/kernel/setup.c | 25 +++++++++++++++++++++++++
arch/arm64/kernel/vdso/gettimeofday.S | 3 +--
drivers/clocksource/arm_arch_timer.c | 8 ++++----
include/clocksource/arm_arch_timer.h | 3 +++
5 files changed, 34 insertions(+), 6 deletions(-)