Converting a working Gentoo setup to a new CPU/mobo

Jkay

Hi!

I've been running Gentoo on a P3 since November, and have been having a great time with it, but now it's time to upgrade.

I bought a dual MP 2400+ mobo ... Question: Can I move the HDD over to the new machine, change the flags and re-compile everything for the new optimizations .. will it BOOT?

Or am I screwed, and have to re-install from stage 1, like 4 months ago?

thanks !!

Jkay · Posted: Sat Feb 15, 2003 1:22 am Post subject:

If I re-compile the kernel with SMP support, and new USE flags .. then move the kernel as an alternate boot line under GRUB .. and then power down the machine ..

And move the HDD to the SMP mobo, and boot, then emerge -e world ..

Would that work?

I basically have the machine nice and set up as I like it

fifo · Guru Joined: 14 Jan 2003 Posts: 437

At least in theory I think it should work. One thing to look out for is, if the hard disk will be seen as a different device in the new computer (for example as /dev/hdb where it was /dev/hda before) then you'll need to modify /etc/fstab. Presumably you'll also want to update your CFLAGS before doing that "emerge -e world"

.

s003apr · Apprentice Joined: 04 Oct 2002 Posts: 162

You could use the livecd to boot with and chroot into the environment, then make a new kernel. That should at least get you a working linux environment. I think.
Just make sure you backup everything important in case it doesn't work and you have to rebuild from scratch.
I definetely don't think it would hurt to try, since starting from scratch is the only alternative.

delta407

Jkay · Posted: Sat Feb 15, 2003 2:29 am Post subject:

Thank you all for these *very* informative posts - one thing tho;

I have read in 2 or 3 posts that march'ing = mp breaks some things in GCC, and even if you have an MP mobo, to march XP ... am I totally wrong here?

I know I have read it more than once on this board.

delta407 · Posted: Sat Feb 15, 2003 3:08 am Post subject:

I've have neither heard of nor expericenced GCC-related problems with -march=athlon-mp on a dual MP 2100+. Of course, your mileage may vary.

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Jkay · Posted: Sat Feb 15, 2003 6:39 pm Post subject:

OK .. that was interesting .. I lost connectivity, and a LOT of modules were borked after I switched my CPU type and march to Athlon-mp .. I did a search from my other PC, and found out about:

# make mrproper

So I did that and Im now able to load the eepro100 module and get online .. but a lot are STILL borked .. I'll keep bonking.

Jkay · Posted: Sat Feb 15, 2003 7:07 pm Post subject:

OK... re-emerging lm_sensors cleared up almost ALL those bad modules.

Now, only:

bmph8ter · n00b Joined: 06 May 2002 Posts: 46

According to Google, the modules that you have left are still LM Sensors stuff. I think maybe another kernel compile (leaving those out-you shouldn't need them) should pretty much fix you up.

Jkay · Posted: Sun Feb 16, 2003 12:23 am Post subject:

Now that things are halfway+ working, I notice (watching Gkrellm2) that the CPU usage for the emerges almost never goes over 50% .. when 1 CPU is 100%, the other drops to 0% .. if I combine them into 1 virtual CPU display, it remains rock steady at 50%

Only running 2 emerges at once forces usage up to 100%

This is with a **test** setting of -j10 BTW ... mem usage is very low as well.

Jkay · Posted: Sun Feb 16, 2003 2:59 am Post subject:

Hm .. a simple re-emerge of alsa-driver will max out the CPUs to 100% but something like a gcc recompile won't .. I don't get it.

GurliGebis · Retired Dev Joined: 08 Aug 2002 Posts: 509

AFAIK gcc recompile forces MAKEOPTS="-j1" , so it will only make one gcc process, so there SMP won't help you.

Correct me if i'm wrong.
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Jkay · Posted: Sun Feb 16, 2003 9:58 pm Post subject:

OK .. so there it is! Some ebuilds simply define a *local* -j value which precludes optimum SMP use ... anyone to second or confirm this tidbit?

GurliGebis · Retired Dev Joined: 08 Aug 2002 Posts: 509

To find an example, try reading the bootstrap.sh script in /usr/portage/scripts/ .
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delta407 · Posted: Mon Feb 17, 2003 2:08 am Post subject: