nathan binkert wrote:
>>  Aside from building a Linux kernel, you will need to build and configure a
>> disk image as well, which is also a fair amount of work.  I've found that,
>> unfortunately due to the long simulation time of Linux boot up, the
>> iteration time to debug the X86_FS bootup is quite long.
>>     
>
> Really, bootup is quite long?  It's pretty fast on Alpha and I
> wouldn't expect that much more to be going on in x86.  There are a lot
> of delay loops during bootup that slow things down.  Have you elided
> all of those?
>
>   Nate
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Just to clarify, multicore bootup of an unmodified kernel -does- work,
at least in the limited circumstances I've tried it (atomic CPU, a
particular version of Linux, etc.). Please correct me if I'm wrong,
Joel, but I'm guessing you mean multicore support with your modified
kernel, right? There are patches out there which cut out the delay
loops, but I don't know if they've actually made it anywhere people can
get at them. I wasn't confident they were correct at the time since I
didn't know how to really test them thoroughly, so I never pushed them
upstream. They do make a noticeable difference, but it's not night and
day. If you boot Linux to the end of kernel initialization where it
starts the first user process, the boot time isn't too bad. If you leave
in all the init scripts that start up the various services turned on by
default in a stage 3 Gentoo image, the time to a login is quite
substantial. If that's what you're doing, you could save *alot* of time
by getting rid of the unnecessary scripts. I've never attempted this
myself, but I'm guessing it isn't too bad.

Gabe
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