Re: Distributed build overhead and Mac Mini vs XServe pricing
Re: Distributed build overhead and Mac Mini vs XServe pricing
- Subject: Re: Distributed build overhead and Mac Mini vs XServe pricing
- From: David Fang <email@hidden>
- Date: Fri, 14 Jan 2005 17:00:28 -0500 (EST)
> The launch this week of the new Mac Mini had be doing some back of
> envelope math and small benchmarking.
Hi all,
Glad I'm not the only one thinking the same thing!
> I benchmarked building one of our larger libraries on a 1.5GHz PowerBook
> G4 : and got an average build time of 395 seconds. I Build the same
> library on my dual 2GHz G5 and got an average build time of 160 seconds.
> So it would appear that the G5 is approx 2.5 times faster than the
> PowerBook.
In my experience with building larger projects, I found that clock
speed was not my limiting factor, but memory. At home, I have a little
old dual 533 MHz G4. Compile-time for a project reduced from 30+ min to
around 6 min, by upgrading from 256 MB to 768 MB RAM. Before the upgrade,
building with MAKEFLAGS -j1 was often necessary (and faster) to prevent
memory from swapping. I normally use Apple's gcc-3.3 with ccache and
distcc. (Sorry, no Xcode/IDE experience here, but I'm still listening!)
My only experience with more massively distributed builds over a
network (same project, 8 to 16-way parallel) is on a FreeBSD-i386 cluster.
Network traffic was sometimes a bottleneck, especially when the
distribution traffic centralized to one server. Using local disks where
possible helped to some extent, especially during the linking phase,
which was heavily I/O bound.
I'd recommend 512 MB per MiniMac/processor if you're going to set
up a distributed compile farm. So you may want to factor some more memory
into the cost estimate.
If anyone has statistics on distributed builds, I'd also like to
know for reference. Clusters of dual-processors perhaps? I'm awaiting
news of the next sub-million-dollar super computer with MacMini's!
"$1M divided by $500 gives us... "
David
> Extrapolating from these numbers a little would give 474 seconds for a
> 1.25Ghz G4 and 140 seconds for dual 2.3 GHz G5 or a scale of 3.4 times
> faster.
>
> Sooo.... an XServe Cluster node with RRP of $2999 is 3.4 times faster
> than a Mac Mini with an RRP of $499, BUT the XServe is 6 times more
> expensive !
>
> I don't think the gigabit ethernet is that much of a contributing factor
> in a distributed build (vs. 100Mbit) but are the overheads of
> distributing to 6 machines vs. 1 machine more than the apparent cost
> savings (or performance benefit from buying more machines for the same
> money).
>
> Anyone have any other data on the build overhead as the number of
> machines increases ? Or am I just trying to hard to justify building a
> stack of Mac Mini's on my desk 8-)
>
> Thanks
>
> Andrew 8-)
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