Re: 2.6.1 slower than 2.4, smp/scsi/sw-raid/reiserfs

Andrew Morton
2004-02-03T03:45:08Z

Philip Martin <philip@codematters.co.uk> wrote:
>
> My test is a software build of about 200 source files (written in C)
> that I usually build using "nice make -j4". Timing the build on
> 2.4.24 I typically get something like
>
> 242.27user 81.06system 2:44.18elapsed 196%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (1742270major+1942279minor)pagefaults 0swaps
>
> and on 2.6.1 I get
>
> 244.08user 116.33system 3:27.40elapsed 173%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (0major+3763670minor)pagefaults 0swaps

I didn't notice the increase in system time.

Could you generate a kernel profile? Add `profile=1' to the kernel boot
command line and run:

sudo readprofile -r
sudo readprofile -M10
time make -j4
readprofile -n -v -m /boot/System.map | sort -n +2 | tail -40 | tee ~/profile.txt >&2

on both 2.4 and 2.6? Make sure the System.map is appropriate to the
currently-running kernel.