[systemd-devel] [External] : Re: firmware times reported were incorrect.

[jiansong Xu]

Got it.
the value of firmware will increase all the time until you power off the machine.
I mean during system warm reset, TSC will not be reseted.
CPU : Skylake

From: Mantas Mikulėnas <grawity at gmail.com>
Sent: 2021年10月13日 20:33
To: jiansong Xu <jiansong.xu at oracle.com>
Cc: systemd-devel at lists.freedesktop.org
Subject: [External] : Re: [systemd-devel] firmware times reported were incorrect.

Looks like boot-timestamps.c first tries to read the ACPI FPDT table (it seems acpi-fpdt.c uses the "OS Loader StartImage Start" and "ExitBootServices Exit" fields), but if that's unavailable, then it uses timestamps stored by systemd-boot in EFI variables (/sys/firmware/efi/efivars/LoaderTime*). The latter seems to be estimating it from RDTSC (src/boot/efi/util.c).

On Wed, Oct 13, 2021 at 3:05 PM jiansong Xu <jiansong.xu at oracle.com<mailto:jiansong.xu at oracle.com>> wrote:
This is bios from oracle, we noticed that the firmware times reported were incorrect.
Startup finished in 59min 7.944s (firmware) + 33.051s (loader) + 4.428s
(kernel) + 1min 18.870s (initrd) + 44.494s (userspace) = 1h 1min 48.789s

May I ask what is the source of the firmware ?  is it read from acpi table?



--
Mantas Mikulėnas
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