[coreboot] [HEADS UP] Time stamps for AGESA boards now measured relatively to start and not ramstage

[Aaron Durbin]

On Sat, Jul 11, 2015 at 11:52 AM, Paul Menzel
<paulepanter at users.sourceforge.net> wrote:
> Am Samstag, den 11.07.2015, 08:00 -0500 schrieb Aaron Durbin:
>> On Sat, Jul 11, 2015 at 4:34 AM, Paul Menzel wrote:
>
> […]
>
>> > With the latest changes we they are measured relatively to system
>> > start.
>> >
>> > $ more asrock/e350m1/4.0-10270-gbd1499d/2015-07-10T13\:23\:53Z/coreboot_timestamps.txt
>> > 12 entries total:
>> >
>> >   10:start of ramstage                                 385,974
>> >   30:device enumeration                                385,982 (8)
>> >   40:device configuration                              480,233 (94,250)
>> >   50:device enable                                     484,088 (3,855)
>> >   60:device initialization                             494,049 (9,960)
>> >   70:device setup done                                 508,368 (14,318)
>> >   75:cbmem post                                        508,736 (368)
>> >   80:write tables                                      508,741 (4)
>> >   90:load payload                                      513,320 (4,579)
>> >   15:starting LZMA decompress (ignore for x86)         513,574 (253)
>> >   16:finished LZMA decompress (ignore for x86)         531,423 (17,848)
>> >   99:selfboot jump                                     531,445 (21)
>>
>> This is actually surprising, but I just looked into it. I see why;
>> it's from my most recent change.
>
> yes, I also assumed it was due to your change set [1].
>
>> If I guard with CONFIG_EARLY_CBMEM_INIT it'd go back to the previous
>> way.
>
> I do too.
>
>> But I actually do like this way (though unintended). The base_time
>> was  never properly exported it from cbmem:
>>
>> > -------for (i = 0; i < tst_p->num_entries; i++) {
>> > ------->-------const struct timestamp_entry *tse_p = tst_p->entries + i;
>> > ------->-------timestamp_print_entry(tse_p->entry_id, tse_p->entry_stamp,
>> > ------->------->-------i ? tse_p[-1].entry_stamp : 0);
>> > -------}
>>
>> It always assumed 0 as a base_time. Without the diff below base_time
>> is actually 0 in this case so you see the accumulated time until
>> ramstage started. I actually think we should fix cbmem.c to not pass 0
>> as prev_stamp for 0th index. It should be passing base_time as well as
>> reporting what base_time was from an informational perspective.
>
> I totally agree.

Care to test this and show the output? See what you like?  I don't
have a machine up to test against at the moment. The same information
is there, but it's shown in a different way in that base_time is
reported as an entry of '1st timestamp'. Your example would change to
something like this:

   0:1st timestamp                                     385,974
 10:start of ramstage                                 385,975 (1)
  30:device enumeration                                385,983 (8)
...

http://review.coreboot.org/10883

>
>> If we want to change it back it's not that hard:
>
> […]
>
> I can’t think of a reason, why we’d want to have the old behavior back.
>
>
> Thanks,
>
> Paul
>
>
>> > [1] http://review.coreboot.org/10880