Hi all, Pentium D is actually an emt64 dual core cpu, so while CFLAGS -march=pentium4 will work, it will be x86-32 instead of x86-64 and of course the compiled apps won't know nothing about the dual core (read almost dual CPU), still it will run, and it will run fast, you may want to recompile the kernel on the data center with vSMP option set, so at least the kernel will know how to manage multithreads between two cores.
On 11/15/06, Alan McKinnon <[EMAIL PROTECTED]> wrote:
On Wednesday 15 November 2006 18:15, Jon M wrote: > Hey again everyone, > > Here is my situation: > > I have CentOS running on a system in a datacenter, but want to switch > to Gentoo. Basically what I've started to do is installed Gentoo on > a P4 3.0Ghz machine at home, and plan on moving it to a Pentium D > 2.66Ghz. Now if I configure/compile/install all my software on the > P4, and the kernel is configured for all the hardware in the other > machine, will it magically work, or will it freak out? My other > concern is that maybe the applications won't be optimized for the > other machine. If this is the case, once it's down there, could I > simply emerge all of my programs one at a time? > > My reason for doing this is to minimize downtime. I didn't want to > take the server offline for a week while I take my time configuring a > new setup. This way it should only be down for maybe 5 minutes while > I do a hard drive swap. > > Thanks in advance for anyones thoughts on this. The one thing you *have* to do is configure the kernel on the compiling machine for the correct hardware that the date center machine has. There's no magic involved, when you boot into the new machine the driver for it's hardware is either there or it isn't. You probably also want to set your CFLAGS to the lowest common denominator cpu - I don't recall off-hand what a Pentium D is, but I imagine the setting will be -march=pentium4. This will avoid the problem of code being compiled with cpu settings that are not present on the target system. And don't worry too much about optimization. We have a word for that - it's called ricing and it's not a good thing. Compile the apps with sane settings and stuff works. Trying to eke out those last 4 cpu cycles just ain't worth the effort... If you need better performance, buy more RAM or faster disks alan -- gentoo-user@gentoo.org mailing list
