Niagara Notes

From SoftXMT
Revision as of 20:24, 28 December 2010 by Skahan (talk | contribs) (Created page with "In our Monday meeting, I volunteered to look at Sun's Niagra chip and try to summarize it. Here's a copy of the basic paper: http://www.cs.pitt.edu/~cho/cs2410/papers/kongetira-...")
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to navigationJump to search

In our Monday meeting, I volunteered to look at Sun's Niagra chip and try to summarize it. Here's a copy of the basic paper:

http://www.cs.pitt.edu/~cho/cs2410/papers/kongetira-ieeemicro05.pdf

Here's a link to the wikipedia article

http://en.wikipedia.org/wiki/UltraSPARC_T1

And here's a link to slides by John Mellow-Crummey at Rice comparing Niagra, the MTA, and the XMT.

http://www.cs.rice.edu/~johnmc/comp522/lecture-notes/COMP522-2010-Lecture3-Multithreading.pdf

Niagra was Sun's code name for their multi-core, multi-threaded processor. Each processor has 4 or more cores (up to 16 nowadays), and each core has hardware support for multiple threads (originally 4, now 8).

The official names for Niagra are UltraSPARC T1, Niagra, 2005 UltraSPARC T2, Niagra 2, 2007 UltraSPARC T2 Plus, 2008 UltraSPARC T3, Niagra 3, 2010 Wipipedia projects at least 2 more generations.

Each release has increased the number of cores per processor, improved floating-point performance, better clock rates, and increased the size of feasible systems.

This last point is the main shortcoming of the design for our purposes: They can only be used to build systems of limited size. Whereas the original Niagra could only be used alone in a single-processor system; the Niagra 3 can be used to build 4-way systems. I expect the limitation arises because of their need to keep their data caches coherent.

Preston