Planned Machines: ASCI Purple, ALC and M&IC MCR
Presented to SOS7
Mark Seager
[email protected]
925-423-3141
ICCD ADH for Advanced Technology
Lawrence Livermore National Laboratory
Q1: What is unique in structure and function of your machine?
Purple’ s unique structure is fat SMPs with 16 rails of Federation interconnect
MCR+ALC’ s unique structure is the shared global file system
However, most important point is that applications are highly mobile between Purple, MCR+ALC, White, Q and other clusters of SMP systems
Purple’ s unique structure is fat SMPs with 16 rails of interconnect
Unique feature of ALC+MCR is Lustre Lite shared file system †
Q2: What characterizes your applications? Examples are: Intensities of message passing, memory utilization, computing, IO, and data.
Applications characterized as multi-physics package simulations
All applications compute/comms intensive
Each package pushes performance envelope along a different dimension
Some packages are MPI latency dominated
Some packages are MPI BW dominated
Memory BW is critical factor, but expensive memory subsystems don’ t perform much better than commodity ones
Q3: What prior experience guided you to this choice?
Mission and Applications
Budgets
Politics
Delivered performance
Balanced risk and cost performance
Strategic Approach: straddle multiple curves to balance risk and opportunity of new disruptive technologies
Three complementary curves
Delivers to today’ s stockpile’ s demanding needs
Production environment
For must have deliverables now
Delivers transition for next generation
Near production environment
Provides cycles for science
Provides cycles for stockpile
Leading to next generation production systems
These are the capacity systems in a strategic capacity/capability mix
Delivers affordable path to petaFLOP/s
Research environment, leading transition to petaflop systems?
Are there other paths to a breakthrough regime by 2006-7?
Q4. Other than your own machine, for your needs what are the best and worst machines? And, why?
Clusters of SMPs with full node OS makes system administration and programming much easier, but scalability is an issue
Vectors suck
10x potential speed-up from vectorization on Cray YMP class machines yielded only 1.5-2x in delivered performance boost to stockpile codes