gcc build / test times on multi-core hosts?

[DJ Delorie]

> Some multi-core processors come with less L2 cache than their multi-CPU
> counterparts.

This, and your other arguments, while valid, apply independently of
the CPU.  There are a lot of factors that determine compile speed.

FYI SGIs tend to have crossbars.

> Was that UMA or NUMA, and how far up could you scale N usefully?

UMA I think.  We generally had just 1 and 2 CPU machines.

> Do you know if software RAID (not so much R as A of ID) is effective
> at avoiding I/O bottlenecks, e.g. will two disks for four cores work
> as well as one disk for two?

Disk is so much slower that CPU that I don't think it matters.
Software RAID is already faster than hardware RAID for common
uniprocessor systems, assuming you don't introduce I/O bottlenecks
(like 33MHz PCI bus).  For example, my server here is a dual opteron,
with an 8-sata controller.  It works because the PCI bus is a 133MHz
64 bit bus, which I calculated was sufficient to host all eight
drives.  I was able to benchmark a 7-disk RAID array at 250MB/s
sustained.