Why bios(generic) is slow?

Eric W. Biederman ebiederman at lnxi.com
Sun Jan 5 00:27:01 CET 2003


hcyun at etri.re.kr writes:

> Hi 
> 
> Can you tell me why generic bios is so slow compared to linuxbios. 
> In other word, why linuxbios is fast? 
> I think "do little thing" is not enough to explain x10 time difference. 
> What does bios do other than linuxbios does and where it spend so much
> time? 

I have wondered that and looked, and on some desktop systems boot up
with a standard BIOS is something like the time LinuxBIOS takes.  But
for server systems, and other lower volume systems I suspect someone
just does a lousy job.

Beyond that.  The easy things to mess up are things like the MTRRs.
If they are not turned on at the appropriate time you can easily get
a 10x slowdown.

Eric




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