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

[Aaron Durbin]

On Sat, Jul 11, 2015 at 12:51 PM, Aaron Durbin <adurbin at google.com> wrote:
> 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

Sorry. You'll see 0 for '1st timestamp' w/ just that patch. However if
you test with the following patch (as my original reply) as well then
you should see the visibility as I noted above:

http://review.coreboot.org/10884

>
>>
>>> 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