Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
CPU Upgrade Questions: K10 -> Piledriver
View unanswered posts
View posts from last 24 hours

 
Reply to topic    Gentoo Forums Forum Index Gentoo on AMD64
View previous topic :: View next topic  
Author Message
soulsource
n00b
n00b


Joined: 25 Jan 2014
Posts: 5

PostPosted: Sat Jan 25, 2014 12:13 pm    Post subject: CPU Upgrade Questions: K10 -> Piledriver Reply with quote

Hi!

I'm planning to replace the CPU of one of my computers. Currently I'm using an Athlon II X2 250e, and I'm thinking about getting the FX-6350. As you can see in the direct comparison, the Piledriver based FX-6350 does not support the 3DNow! instructions. Currently I'm using the following CFLAGS:
Code:
CFLAGS="-O2 -march=amdfam10 -pipe -mmmx -msse -msse2 -msse3 -msse4a -m3dnow"

Also, the 3dnow and 3dnowext USE flags are currently enabled.
This leads me to the following questions:

  • Do I have to expect, that due to the -m3dnow flag, all binaries of my current Gentoo installation will fail to run on the new CPU?
  • If yes: What will I have to recompile before changing the CPU, in order to be able to boot and to compile ebuilds after the CPU-change, and which CFLAGS would I have to use for this recompilation?
  • If I do something wrong and the system won't boot after replacing the CPU, is there a way to recompile @system and @world without changing the CPU back (as this would mean disassembling the whole PC, thanks to the nonstandard CPU cooler)?

I'm planning to recompile my whole installation after changing the CPU, in order to get the benefits of the additional instruction sets available, yet I'd like to avoid recompiling everything to a safe common feature set before changing the CPU, since my current CPU is rather slow...

Thanks in advance for any help.
Back to top
View user's profile Send private message
Maitreya
Apprentice
Apprentice


Joined: 11 Jan 2006
Posts: 217

PostPosted: Sat Jan 25, 2014 2:23 pm    Post subject: Reply with quote

I don't think you will have a lot of trouble as there are barelly any calls made to 3dnow nowadays.
This is not a garantee btw. If you want to be sure at least get your toolchain to something more generic.
"mmx sse sse2 sse3 sse4a 3dnow" are implied by amdfam10. No need to put them in a second time.
So if you wan't to be sure you really can get @system @world compiled; get your toolchain built on something like:
CFLAGS="-O2 -march=x86-64 -pipe -mtune=bdver2"

This way it will always run on "a" x86-64 and still has optimizations later for recompiling to native or -march=bdver2
Back to top
View user's profile Send private message
soulsource
n00b
n00b


Joined: 25 Jan 2014
Posts: 5

PostPosted: Mon Jan 27, 2014 10:56 pm    Post subject: Reply with quote

Thanks a lot. I'm going to recompile my toolchain with safe CFLAGS so I can chroot and build stuff if the system doesn't boot afterwards. Is there a simple command to get all ebuilds which are required to build software and all the libraries they are linked against recompiled? At the moment the best I can think of is running "emerge -eav @system", which includes bash, coreutils, make, binutils, gcc, glibc, and, as it seems also all their dependencies. Nevertheless, I'm afraid it might take several days to run this, as it also includes browsers, icedtea and libreoffice...
Back to top
View user's profile Send private message
soulsource
n00b
n00b


Joined: 25 Jan 2014
Posts: 5

PostPosted: Mon Feb 03, 2014 11:35 pm    Post subject: Reply with quote

Just if anyone stumbles across this: As planned, I ran 'emerge -eav @system' and after the CPU was replaced, everything was running fine (apart from some struggle due to a bug in kernel 3.12.5, which was solved by updating to 3.12.9). I'm now recompiling everything to get the benefits from -march=native and then I'm hopefully done ;-)
Back to top
View user's profile Send private message
yoshi314
l33t
l33t


Joined: 30 Dec 2004
Posts: 819
Location: PL

PostPosted: Wed Apr 09, 2014 12:28 pm    Post subject: Re: CPU Upgrade Questions: K10 -> Piledriver Reply with quote

soulsource wrote:


[*] Do I have to expect, that due to the -m3dnow flag, all binaries of my current Gentoo installation will fail to run on the new CPU?


if anyone still has a similar upgrade planned :

in my case, only a handful of things went wrong :

- mpv, mplayer2, mplayer would crash and only on a certain h264 video files (vlc worked fine i think), and only with -vo xv ( -vo gl3 worked fine, for instance )
- mpd, i think

i updated from old amd 64 x2 3800+ to a10-6700.

-march=native is a major trap if new cpu actually removes some cpu instructions.
_________________
~amd64, ~x86
shrink your /usr/portage with squashfs+aufs
Back to top
View user's profile Send private message
kurisu
Tux's lil' helper
Tux's lil' helper


Joined: 19 Jan 2011
Posts: 85
Location: Munich, Germany

PostPosted: Tue May 20, 2014 9:07 pm    Post subject: Re: CPU Upgrade Questions: K10 -> Piledriver Reply with quote

yoshi314 wrote:
-march=native is a major trap if new cpu actually removes some cpu instructions.

True, but not critical in this case since it does not affect system related stuff. I have recently gone from K10 to Piledriver as well sticking to -march=native all along the way. Abandoning 3dnow and 3dnowext USE flags later on did not cause me any issues that emerge -uDN @world could not fix. However, in order to be safe, one could of course do so beforehand.
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Gentoo on AMD64 All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum