Re: [gentoo-user] distcc and crossdev, anyone?

[Petri Rosenström]

On Tue, Dec 21, 2010 at 1:56 AM, Bill Longman <bill.longman@×××××.com>wrote:

> On 12/18/2010 07:15 AM, Peter Humphrey wrote:
> > On Saturday 18 December 2010 10:18:43 Neil Bothwick wrote:
> >
> >> I've found there's just too much overhead with distcc, plus much of
> >> the work is still done locally.
> >
> > I expected that but I wanted to try it to see.
> >
> >> I have a couple of Atom boxes, a server and a netbook, and I've set up
> >> a chroot for each on my workstation. In the chroot I have
> >> FEATURES=buildpkg, using an NFS mounted PKGDIR available to both
> >> computers, then I emerge -k on the Atom box.
> >
> > Maybe I'll go this way instead. Thanks for the idea, which is similar to
> > one from YoYo Siska three days ago.
>
> I had my Atom 330 running as a distcc client for a long time. I have
> several other speedy CPUs alongside it so it could spray plenty of
> compilation requests out its gigabit NIC to various much beefier
> machines. But as Neil stated, lots of the processing still occurs
> locally, so as you increase nodes, you need to decrease the amount of
> compilation done locally. With such a disparity between CPU, it takes
> less time overall to just do it the way Neil describes - make a chroot
> and then just build it with the intention that the slow CPUs will use
> the binary build.
>
> You still need lots of CPU to compile, so a slow machine will still
> compile slowly. If your client is a pokey 1.6GHz Atom and you're sending
> jobs to two quad core 3GHz CPUs on your subnet, you'll soon see that the
> Atom's load goes up toward 8 as it tries to bring those remote jobs
> back. So, the four threads on my 330 get completely filled up and it's
> dog slow. And it's even more painful when you use the preprocessor
> because the client must zip the compile "construction" before it ships
> it out, so you have even less CPU available for compilation (although
> you get some of that back).
>
> All said and done, my back-of-the-napkin and seat-of-the-pants
> calculation tells me that I still get a _minimum_ 25% reduction in
> overall compile times with distcc. That's my experience after using
> distcc for almost ten years with various configurations of network and
> CPUs.
>
>
I have set up my system as Neil described chroots for different systems on a
fast computer. I use this setup for my gentoo boxes I have and it has made
my compilations fast(er). I tried to use distcc with one U2300 celeron and
some amd 4x cpu and the amd didn't really compile, because the U2300 was a
bottleneck, so I decided to chroot it and been happy ever since.

I have been thinking about a tool that could automagically start the emerge
on the remote system. I thought about just ssh in with a script. But I am on
so many flaky Internet connections that it isn't reliable enough.

Petri