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

[Nick Piggin]

Philip Martin wrote:

> Andrew Morton <akpm@xxxxxxxx> writes:
>
>
> > > 2.6.1
> > Odd.  Are you really sure that it was the correct System.map?
>
> I think so. I always build kernels using Debian's kernel-package so
> both vmlinuz and System.map get placed into a .deb package as
> vmlinuz-2.6.1 and System.map-2.6.1.
>
> $ ls -l /boot/Sys*
> -rw-r--r--    1 root     root       492205 Dec  1 19:27 /boot/System.map-2.4.23
> -rw-r--r--    1 root     root       492205 Jan  5 21:21 /boot/System.map-2.4.24
> -rw-r--r--    1 root     root       715800 Feb  1 21:02 /boot/System.map-2.6.1
>
> $ ls -l /boot/vm*
> -rw-r--r--    1 root     root       880826 Dec  1 19:27 /boot/vmlinuz-2.4.23
> -rw-r--r--    1 root     root       880822 Jan  5 21:21 /boot/vmlinuz-2.4.24
> -rw-r--r--    1 root     root      1095040 Feb  1 21:02 /boot/vmlinuz-2.6.1
>
> Hmm, I see that my 2.6.1 image is 25% bigger than 2.4.24, I'd not
> noticed that before.

That's progress for you...

> I have just tried another 2.6 profile run and got similar results.
>
> 248.88user 122.00system 3:41.18elapsed 167%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (453major+3770323minor)pagefaults 0swaps

Thanks for your patience. What are you building, by the way? It
slipped my mind.

You could try an experimental VM patch out if you're feeling brave.
Don't know if it will do you any good or not. You'll have to use
this patch against the 2.6.2-rc3-mm1 kernel.

What I really want to know though, is why it appears like 2.6 is
doing twice as much writeout even at the same vm thresholds as 2.4.

Nick

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