Subject: Re: [RFC PATCH] time: introduce BOOT_TIME_TRACKER and minimal boot timestamp

From: Thomas Gleixner <[email-masked]>
Date: Tue, 02 Sep 2025 12:52:37 +0200

On Tue, Sep 02 2025 at 12:32, Kaiwan N. Billimoria wrote:
> So, just confirming: here 1409443611 divided by 200 MHz gives us 7.047218055s
> since boot, and thus the actual timestamp here is that plus 0.000001s yes?
> (Over 7s here? yes, it's just that I haven't yet setup U-Boot properly for uSD
> card boot, thus am manually loading commands in U-Boot to boot up, that's all).

Looks about right.

> A question (perhaps very stupid): will the hwcnt - the output of the read() -
> be guaranteed to be (close to) the number of increments since processor
> power-up (or reset)? Meaning, it's simply a hardware feature and agnostic to
> what code the core was executing (ROM/BL/kernel), yes?

Under the assumption that nothing on the way resets the counter.

Thanks

        tglx