[coreboot] Timing via serial port

[Carl-Daniel Hailfinger]

On 19.04.2009 05:05, Kevin O'Connor wrote:
> On Sat, Apr 18, 2009 at 09:14:06PM -0400, Kevin O'Connor wrote:
>   
>> The biggest SeaBIOS time consumers:
>>     
> [...]
>   
>> 425ms - scanning for option roms
>>     
>
> I tracked this one down - it's the cost of CBFS and reading the flash.
> Of the 425ms, 90ms is spent copying the via vga rom.  The remaining
> time is spent doing CBFS searches - there are 18 pci devices on this
> machine and for each one SeaBIOS scans CBFS for "pciVVVV,DDDD.rom".
> Because none of these files were actually present, SeaBIOS ended up
> walking all the flash freespace each time.  All those flash accesses
> add up.
>   

And again we see that we'd be better off with LAR instead of CBFS. Every
single problem we solved with LAR has to be solved again with CBFS. This
time, it's zerofill (the feature which makes sure you don't have to walk
all the free space).


>> 260ms - initializing ATA drives
>>     
>
> I wonder if I can skip the ATA reset on the first boot - the device
> should have just gone through a hw reset anyway...
>   

In theory, this can be skipped, but you have to wait until the disks are
ready.

Regards,
Carl-Daniel

-- 
http://www.hailfinger.org/