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wichtounet Tux's lil' helper
Joined: 17 Mar 2012 Posts: 122
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Posted: Tue Jun 18, 2013 7:32 am Post subject: Can I change my processor without reinstalling ? |
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Hi,
I will soon upgrade my configuration (motherboard,ram and processor).
I would like to know if it is possible without reinstalling everything. I don't mind recompiling everything as it can run when I'm at work, but I do not want to reinstall everything.
I have an old Core 2 Duo and my system is compiled with march=native. I will upgrade to a new Haswell i7.
What I want to do is:
With the old processor:
Remove march=native
Recompile everything
With the new processor:
Set march=native again
Recompile again everything
Can something like that works ?
Thanks |
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DawgG l33t
Joined: 17 Sep 2003 Posts: 866
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Posted: Tue Jun 18, 2013 8:42 am Post subject: |
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as long as you don't change ARCH i think it should be possible to just boot the "old" system with a rescue-cd, then chroot into it and do sth. like
if you change the motherboard/hardware you have to configure the kernel accordingly.
of course, when doing major changes like that it's mandatory to have backups of EVERYTHING before even trying anything.
GOOD LUCK! _________________ DUMM KLICKT GUT. |
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Maitreya Guru
Joined: 11 Jan 2006 Posts: 441
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Posted: Tue Jun 18, 2013 9:29 am Post subject: |
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I don't think gcc has a lot of different optimizations that make native/core2 compilations as opposed to native/core-avx2 that would make it incompatible to run.
Maybe not as efficient.
Try to boot it as it will probably JustWork™
If it doesn't; Like DawgG said : keep your install somewhere safe |
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bbgermany Veteran
Joined: 21 Feb 2005 Posts: 1844 Location: Oranienburg/Germany
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Posted: Tue Jun 18, 2013 10:00 am Post subject: |
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Hi,
According to this: http://ark.intel.com/compare/27258,35428,35605,75125 the latest core2 compared to haswell i7 they only added features. so you should be fine. I would say, if you go with amd instead of intel you need to remove -march=native with recompiling everything before moving.
bb _________________ Desktop: Ryzen 5 5600G, 32GB, 2TB, RX7600
Notebook: Dell XPS 13 9370, 16GB, 1TB
Server #1: Ryzen 5 Pro 4650G, 64GB, 16.5TB
Server #2: Ryzen 4800H, 32GB, 22TB |
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chithanh Developer
Joined: 05 Aug 2006 Posts: 2158 Location: Berlin, Germany
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Posted: Tue Jun 18, 2013 6:11 pm Post subject: |
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Yes, i7 has a superset of core2 instructions.
But even when not (e.g. switching from and to Atom, or between Intel and AMD), you can set generic CFLAGS and "emerge -e @system" on the old CPU, then set -march=native again and "emerge -e @world" on the new CPU. |
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wichtounet Tux's lil' helper
Joined: 17 Mar 2012 Posts: 122
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Posted: Wed Jun 19, 2013 6:43 am Post subject: |
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Thanks a lot for all your answers
I will try first without changing anything to see if it works and then recompile again to profit from the latest instructions. I'll come back here if I have problems |
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mattst88 Developer
Joined: 28 Oct 2004 Posts: 422
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Posted: Wed Jun 19, 2013 9:48 pm Post subject: |
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There are only new instructions from your old CPU to Haswell. It will just work without rebuilding everything. Don't waste your time. _________________ My Wiki page |
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