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

[Paul Menzel]

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.

> 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
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