Re: [PATCH] sched_clock: Add option to use absolute time against hardware clock reset

[Feng Tang]

On Mon, Sep 07, 2026 at 10:37:03AM +0100, Marc Zyngier wrote:
[...]
> > -	pr_info("sched_clock: %u bits at %lu%cHz, resolution %lluns, wraps every %lluns\n",
> > -		bits, r, r_unit, res, wrap);
> > +	/* Calculate the time since last counter resetting to 0 */
> > +	reset_ns = mul_u64_u64_div_u64(new_epoch, NSEC_PER_SEC, rate);
> > +
> > +	pr_info("sched_clock: %u bits at %lu%cHz, resolution %lluns, wraps every %lluns, has run %lluns since counter reset\n",
> > +		bits, r, r_unit, res, wrap, reset_ns);
> >  
> >  	/* Enable IRQ time accounting if we have a fast enough sched_clock() */
> >  	if (irqtime > 0 || (irqtime == -1 && rate >= 1000000))
> > 
> 
> Which is what people have done locally since the beginning of times.
> And the only time this is actually useful is when bringing up new
> HW/FW that is broken.
> 
> So why the need to put that in an upstream kernel, instead of being as
> part of your debug toolbox? I don't think the kernel shouldn't be the
> recipient of this sort of stuff.

I see your point now, thanks!

- Feng

> 
> 	M.
> 
> -- 
> Without deviation from the norm, progress is not possible.