[systemd-devel] bootloader time on a non-EFI bootloader

[Lennart Poettering]

On Thu, 09.04.15 18:42, Kay Sievers (kay at vrfy.org) wrote:

> > Also note that ACPI 5.0 exports this timing information in a generic
> > way anyway. Given that ACPI is fairly standard and apparently is even
> > what embedded is standardizing on I'd be open to adding native support
> > for parsing this info from ACPI to systemd, if it's easy enough.
> 
> The ACPI "Firmware Basic Boot Performance Data Record" provides some
> values on more recent firmware versions:
>   $ sudo ./test-boot-timestamp
>   ACPI FPDT: loader start=7.994s exit=8.115s duration=120ms
>   EFI Loader: start=7.994s exit=8.080s duration=86ms
>   Firmware began 8.115550s before kernel.
>   Loader began 120.791ms before kernel.
> 
> The ACPI values are accessible after the system booted up, just like
> EFI variables are.
> 
> For platforms which do not have anything like that, the kernel boot
> protocol still sounds like the closest thing to fill the gap.

Oh, indeed, I completely missed that we already have ACPI parsing
support for this in place!

Lennart

-- 
Lennart Poettering, Red Hat