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SubjectRe: [PATCH v7 6/6] x86/tsc: use tsc early
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Hi Pavel,

At 11/03/2017 01:26 AM, Pavel Tatashin wrote:
> tsc_early_init():
> Determines offset, shift and multiplier for the early clock based on the
> TSC frequency.
>
> tsc_early_fini()
> Implement the finish part of early tsc feature, prints message about the
> offset, which can be useful to find out how much time was spent in post and
> boot manager (if TSC starts from 0 during boot)
>
> sched_clock_early():
> TSC based implementation of early clock.
>
> Call tsc_early_init() to initialize early boot time stamps functionality on
> the supported x86 platforms, and call tsc_early_fini() to finish this
> feature after permanent clock has been initialized.
>
> Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
> ---
> arch/x86/include/asm/tsc.h | 4 +++
> arch/x86/kernel/setup.c | 10 ++++--
> arch/x86/kernel/time.c | 1 +
> arch/x86/kernel/tsc.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 94 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
> index f5e6f1c417df..6dc9618b24e3 100644
> --- a/arch/x86/include/asm/tsc.h
> +++ b/arch/x86/include/asm/tsc.h
> @@ -50,11 +50,15 @@ extern bool tsc_store_and_check_tsc_adjust(bool bootcpu);
> extern void tsc_verify_tsc_adjust(bool resume);
> extern void check_tsc_sync_source(int cpu);
> extern void check_tsc_sync_target(void);
> +void tsc_early_init(unsigned int khz);
> +void tsc_early_fini(void);
> #else
> static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; }
> static inline void tsc_verify_tsc_adjust(bool resume) { }
> static inline void check_tsc_sync_source(int cpu) { }
> static inline void check_tsc_sync_target(void) { }
> +static inline void tsc_early_init(unsigned int khz) { }
> +static inline void tsc_early_fini(void) { }
> #endif
>
> extern int notsc_setup(char *);
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 0957dd73d127..3df8be642b80 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -822,7 +822,11 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
> return 0;
> }
>
> -static void __init simple_udelay_calibration(void)
> +/*
> + * Initialize early tsc to show early boot timestamps, and also loops_per_jiffy
> + * for udelay
> + */
> +static void __init early_clock_calibration(void)

Commit:

eb496063c990 ("x86/timers: Move the simple udelay calibration to tsc.h")

moves this function to tsc.h and renames it in tip tree[1].

I guess using this commit, we can simplify this patch.

As this series, except the 2rd patch, is worked for x86, how about let
this series be based on tip.

BTW, I am testing your patches, will give you result later.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git

Thanks,
dou


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