Can I run binaries compiled with a different -march flag?

jerann · n00b Joined: 26 Jan 2005 Posts: 67

I probably know the answer to this already, but I thought I'd ask on the off chance that I'm wrong. I've got a laptop has a tendency to overheat when compiling stuff, so I've been using the instructions at http://gentoo-wiki.com/HOWTO_Emerge_on_very_slow_systems to emerge stuff on my laptop using my desktop. The basic idea is to export the root directory on the laptop with NFS and chroot to it on the desktop. It works great - I recompiled the whole system that way and have not encountered any problems at all. Well, I've also got a home server that I'd like to be able to use for the same purpose, but I hit a snag - the make.conf on the laptop specifies CFLAGS="-O2 march=prescott -pipe -fomitframepointer". It uses an Intel Pentium 4 2.80 GHz Mobile processor, and my desktop uses an AMD Athlon X2 3800+ (overclocked to 2.4 GHz). Apparently, the Athlon X2 runs binaries compiled with -march=prescott just fine, but my server has an Athlon XP 3200+ 2.2 GHz, which will not run binaries like that - it keeps saying "Illegal instruction" when I chroot to the laptop and try to execute pretty much anything (apparently bash runs, but env-update will not). So, my question is - can I somehow run the binaries from my laptop on my server (without recompiling with less strict cflags on the laptop)? I doubt it matters, but the server is running Debian - not Gentoo. It'd be nice to do this on my server, but obviously I could still just use the desktop if I didn't have another choice.

vaxbrat · l33t Joined: 05 Oct 2005 Posts: 731 Location: DC Burbs

That XP is too old to handle some of the Prescott instructions. It could probably handle just plain ole Pentium 4 if you throttle back the march. I'm trying to remember off the top of my head what might have changed (SSE2?)

Genone · Posted: Mon Jul 16, 2007 11:15 am Post subject: Re: Athlon-XP too old

Cyker · Veteran Joined: 15 Jun 2006 Posts: 1746

Yeah... you'll either have to use -mtune instead of -march, or just use the lowest common instruction set they both can do...

Alternatively, you could use -mno-sse2 and/or -mno-sse3 if that's all that is wrong.

MotivatedTea · Posted: Tue Jul 17, 2007 3:11 pm Post subject:

As a totally different alternative to your overheating problem: I've got a laptop that also tends to overheat, so I just use cpufrequtils to reduce the maximum CPU speed while I'm running emerges. Takes a little longer, but I normally let large upgrades go overnight anyways. (It's a Pentium M 2.0GHz, but it gets very hot running at 2.0GHz for an extended period of time, so I generally throttle it to 1.6GHz.)

jerann · n00b Joined: 26 Jan 2005 Posts: 67

OK - that was pretty much the response I'd anticipated.