Gentoo Archives: gentoo-mips

From: Stuart Longland <redhatter@g.o>
To: gentoo-mips@l.g.o
Subject: Re: [gentoo-mips] is gentoo-mips right for me?
Date: Tue, 27 Dec 2005 12:38:54
In Reply to: Re: [gentoo-mips] is gentoo-mips right for me? by Kumba
Kumba wrote:
> Tomasz Chmielewski wrote: >> Stephen P. Becker wrote: > >>> That and I don't think qemu is particularly fast. >> >> Whatever slow it is, it will be faster than trying to compile anything >> natively on these tiny routers :) > > Thou hath not tryeth to compileth glibc upon a RaQ2 of Cobalt, have > thee? :) > > Granted you can jack the RAM in a cobalt to a decent size for it to suck > down behemoths like glibc, assuming you got an emulator to work, the > emulator would likely be slower than a RaQ2, and probably slower than > native compiles. The only upside is being able to feed the emulated > environment more RAM. >
Last I heard... QEMU was emulating a ~30MHz MIPS machine... on a modern (>2GHz) x86 machine. Your router most likely has a clock speed in the range of 100~200MHz; much faster than QEMU. Others, like gxemul (which may be better suited to your needs) suffer similar performance losses.
>> So, this means, that if I build a whole gentoo-mips under qemu - >> sounds easy, doesn't it? :), with mipsel uclibc stages/-march=mips32, >> almost each and every binary copied from such a system should run on >> these tiny routers? > > > We generally discourage people who are new to non-x86 from venturing off > into experiments like this initially. The experiment can sometimes be > overwhelming, anf frustration eventually kills off any motivation to > complete it. Our usual suggestion is to get yourself a cheap SGI Box, > like an Indy or an O2, play with it for a few months and learn how MIPS > works, then you'll have an idea of how stuff works in comparison to > their more inefficient x86 cousins. Other archs, like Sparc, work well > too as non-x86 playtoys. Then the original task can sometimes be easier > (but not always).
Better still... get a Cobalt machine if you can. The Cobalt machines run a little-endian MIPS4 CPU, which, while they can't run MIPS32 ISA binaries, they are at least the right endianness to be able to build stuff natively for your router. And although they are quite slow (generally 250MHz, and no secondary cache), they'll be a lot faster than most emulators out there. This, with a suitable µClibc-based chroot environment, should do quite well for the task. I still stand by what Kumba said ... start with something that is officially well-supported (e.g. an SGI box, or a Qube2/RaQ2) to get familiar with MIPS ... then work towards building for the router. :-) -- Stuart Longland (aka Redhatter) .'''. Gentoo Linux/MIPS Cobalt and Docs Developer '.'` : . . . . . . . . . . . . . . . . . . . . . . .'.' :.'


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