Re: [PATCH v2 0/3] x86/tsc: Remove some magic constants

From: Petr Tesarik

Date: Tue Oct 27 2026 - 09:05:32 EST


Hi all,

what about this series? It's not super-important, but neither should it
be too hard to review...

Petr T

On Wed, 14 Oct 2026 15:29:29 +0200
Petr Tesarik <ptesarik@xxxxxxxx> wrote:

> The TSC code is full of various magic constants, making it difficult to
> understand the calculations. This patch series tries to document their
> actual meaning.
>
> No functional change intended, but the code is not bit-for-bit
> identical; some 32-bit multiplications are converted into 64-bit
> multiplications, because HZ_PER_KHZ is an unsigned long. If anything,
> this should reduce the risk of arithmetic overflow.
>
> Changes from v1:
> - Use TICK_NSEC instead of (NSEC_PER_SEC / HZ)
> - Use HZ_PER_KHZ and KHZ_PER_MHZ from <linux/units.h>
>
> Petr Tesarik (3):
> x86/tsc: Replace magic constants with xxx_PER_SEC
> x86/tsc: Use HZ_PER_KHZ and KHZ_PER_MHZ
> x86/tsc: Use TSC_CALIBRATE_MULT for the TSC multiplier
>
> arch/x86/kernel/tsc.c | 54 +++++++++++++++++++++----------------------
> 1 file changed, 27 insertions(+), 27 deletions(-)
>