Marc Hamilton's Weblog: Marc Hamilton's Weblog

Huge excitement this week about using Chip Multithreading for web services workloads but CMT is equally applicable to HPC applications, just not necessarily with the UltraSPARC T1 processor. While the UltraSPARC T1 is a new processor, Sun has actually been developing CMT processors for many years, witness Marc Tremblay's 2000 ACM article on Sun's earlier MAJC processor which probably holds the title of the world's first CMT processor. So why won't you see HPC benchmarks for the UltraSPARC T1? As pointed out by James Laudon's paper, the eight cores in the UltraSPARC T1 share a single floating point unit. This is actually a good thing for folks running integer based web services and database workloads that don't require power-hungry floating point performance. However, as Moore's law allows more transistors to be placed on the same size die year over year, look for future Sun CMT processors to address not only web services workloads but also floating point intensive HPC workloads as well.

That leads to Marc's cheat sheet for Sun product and processor positioning:

For web services workloads and integer based throughput intensive applications requiring less than 32 GB, you can't beat the T1000/T2000 with the UltraSPARC T1 processor

For single treaded HPC and floating point performance, Sun Fire x64 (x86, 64-bit) including Sun Fire x2100, x4100, and x4200, along with v20z and v40z.

For SMP applications requiring > 16 cores or > 64 GB memory, use Sun Fire Enterprise servers with the UltraSPARC IV+ processor