FC1 boot freeze on IBM Summit chipset

[Choo Zhi Min]

Hi,

I install FC1 on IBM x445 (Summit chipset, 4GB RAM, dual Xeon 3.0GHz). During 
bootup:

1)  uniprocessor kernel boot up ok, with kernel 2115 and 2179, with irqbalance 
on and off, as in $chkconfig irqbalance [on|off], same below.

2)  smp kernel freeze after seeing login screen, with kernel 2115 and 2179, with 
irqbalance on 

3)  smp kernel boot up ok, with kernel 2115 and 2179, with irqbalance off 

4)  recompile kernel 2179 using config file from /usr/src/linux-2.
4/configs/kernel-2.4.22-i686-smp.config, but choose CONFIG_X86_NUMA=y and 
CONFIG_X86_SUMMIT=y. Result: same behaviour as (2) and (3)

5)  compile kernel 2.4.26 from kernel.org using config file with all default 
setting, but choose CONFIG_X86_NUMA=y and CONFIG_X86_SUMMIT=y. Boot up ok, no 
freeze, with irqbalance on and off. Result: same as (1)


Why number (4) don't work after enabling support for summit chipset?

It seems that my choice is either (3) or (5). 
In (3), how is irqbalance=off going to impact performance?
In (5), is NPTL available in 2.4.26?

My application (python) is going to be bound to one cpu per process. So which 
option is better: irqbalance or NPTL? 


Thanks!

Regards,
ZhiMin