[debian-knoppix] Performance issues on SMP vs UP (was Re: non-SMP kernel)

[Masaharu Goto <magotou@fubyshare.gr.jp>]

From Japan

Hi, Guten tag !

I'm considering about remastered KNOPPIX with UP kernel built by my own.
Main reason to do this is not for disk consumptions but performance
improvements. As I heard, SMP kernel is slower than UP one, reaches 30%
down especially I/O operations and rather problem if we run knoppix on
slower PCs environments.

"nosmp" parametrer does not contribute to speedups. Here are reports 
generated by "bonnie++";

============================================================================
Normal boot--------------
Version 1.02c       ------Sequential Output------ --Sequential Input- 
--Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- 
--Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec 
%CP
cyan-knoppix     1G 11727  74 34294  49 14078  17 12527  94 40749  17 131.50
                    ------Sequential Create------ --------Random 
Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- 
-Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec 
%CP
                 16   493  98 +++++ +++ 32222 100   509  98 +++++ +++  2048
97

"knoppix nosmp" boot---------------
Version 1.02c       ------Sequential Output------ --Sequential Input- 
--Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- 
--Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec 
%CP
cyan-knoppix     1G 11774  95 34082  56 14017  17 12213  76 39305  16 124.70
                    ------Sequential Create------ --------Random 
Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- 
-Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec 
%CP
                 16   509  98 +++++ +++ 32583 101   534  97 +++++ +++  2051
97
============================================================================
No significant differences there between normal boot and "nosmp" boot.

# Please don't ask me details about more about these results now,
# I'm now only wanting to have some experiment session for UP kernel:-)

I tried "apt-get install kernel-source-2.4.20" and duplicate knoppix
distributed ".config" file from /usr/src/linux-2.4.20-xfs to current 
kernel source tree root. Built ;

# cd /usr/src/linux
# vi .config
[turn SMP option off]
# make-kpkg clean
# make-kpkg --revision=myown kernel-image

When I tried to build my own for the first time, use "make menuconfig".
The try was resulted in unexpectedly increased vmlinuz. So I edit .config
by hand.

# dpkg - kernel-image-2.4.20_myown_i386.deb

Build process has finished successfuly.Then I create initrd sutffs;

# mkinitrd -o /boot/initrd-2.4.20 /lib/modules/2.4.20
# cd /boot
# gzip initrd-2.4.20

/boot/initrd-2.4.20.gz has created with very huge size....

-rw-r--r--    1 root     root      2618654 Feb 28 21:30 initrd-2.4.20.gz

vs.

-rw-r--r--    1 root     root       147374 Feb 10 07:50 initrd.gz

There is "MODULES=most" directives in /etc/mkinitrd/mkinitrd.conf and
that makes initrd huge...I think.

Then I edited /etc/lilo.conf and wrote boot secto then reboot....
Kernel panic occured because system could not mount root filesystem.
Well, it seems that I made some mistakes.

Klaus, would you please give me clues to rebuild own kernel for current
knoppix ?

 - Where/How can I get sources and patchs to build kernel-2.4.20-xfs ?
 - Contents of your /etc/mkinitrd/* files( mkinitrd.conf, modules)
 - Related advices.

Or anybody tried to rebuild UP kernel and measured performance ?

Thanks in advance and regards,
Max
-- 
Masaharu "Max" Goto
GnuPG Key fingerprint = 4D69 6B1D 484D 999C EDA7  2853 32AF 0C86 9323 3DDB

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