Kernel 2.2.19 crashes, 2.4.4 bad performance

["T. Weyergraf" <kirk@colinet.de>]

Hi all,

triggered by a discussion in irc.openprojects.net, #alphalinux, I've spend some time
on benchmarking various linux kernels and came across some very strange results.

Platform: Dual 667 UP2000, 1.5gig ram, 3 adaptecs with 5 disks total, serial console.

Kernel 2.4.4 seems to suffer a *tremendous* performance impact, compared to 2.2.19.
A 'time make -j4 boot' of the kernel-2.4.4 sources gives the following compile-times:
        
        2.4.4         2.2.19       
real   3m58        2m38
user  4m23        2m23
sys    0m14       0m11

Several other tests seem to indicate a similar decrease in performance wrt real-time, some
of them being CPU and/or memory-bound only.

In addition to that, i've noticed, that kernel 2.2.19 frequently crashes, after giving the
well-known "stuck spinlock" messages in rather random processes. No panics are given,
the system just freezes completely ( no ping and the like ).

So, obviously, my two questions are:

1. Has anybody ever observed the performance impact, i'm seeing with kernel 2.4.x ?
2. Since i moved to kernel 2.4.x very early for various reasons, I would like to know, which
    of the recent 2.2.x kernels can be considered stable on a alpha/SMP platform ( ideally being
    a UP2000 as well ).

I'm a bit confused here ;-)

Regards,
Thomas Weyergraf


-- 
Thomas Weyergraf                                                kirk@colinet.de
My Favorite IA64 Opcode-guess ( see arch/ia64/lib/memset.S )
"br.ret.spnt.few" - got back from getting beer, did not spend a lot.