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					WildFire: A Scalable Path
        for SMPs
  Erick Hagersten and Michael Koster
         Sun Microsystems Inc.
      Presented by Terry Arnold II
             Introduction
 What was the goal?
 How did they achieve it?
 CMR
 HAS
 Competitive Comparisons
 Results
 Questions
               The Goal
 In the past people have been skeptical
  about the ability of SMPs to continue to
  scale due to their bandwidth limitations
 The trend has been to switch to cc-NUMA
 To improve the scalability of SMP
  technologies
            Cc-NUMA issues
 Great scalability but have less than
  optimal “access patterns”
 Require high software optimization for
  capacity and conflict misses
 Non trivial scheduling, etc. (resource and
  memory management)
                   How?
 The answer is the same as the answer to
  all engineering problems, that is, throwing
  new acronyms at the problem
 Coherent Memory Replication (CMR)
 Hierarchical Affinity Scheduling (HAS)
 Both of these exploit locality as a means
  of increasing performance (that is for
  OLTP workloads)
The Overview
            The Acronyms: CMR
   S-COMA with fixed home locations for each
    address
   Shadow physical pages
   Coherence at hardware level (64 byte)
   Things start out cc-NUMA and changed into CMR
    based on hardware counters that monitor
    memory access patterns
   Limitations – memory-resident pages and large
    physical pages can only be replicated explicitly
        The Acronyms: HAS
 Schedules in the following way:
 Last processor it ran on
 Same node processor
 Remote node processor (when load
  balances exceeds “threshold”)
           Implementation
 2 ASICs – NIAC (coherence), NIDC (bit
  sliced interconnect)
 These improve upon latency of a switch
 NIAC – Interface and Global-Coherence
  Layer
 Translators and Counters
    Competition
   The SGI Origin and
    Sequent’s NUMA-Q
Results 1
Results 2
                  Questions?


Is this “solution” too dependent on the software
(kernel modifications)?


How compatible are CMR and HAS with the other DSM
solutions?

				
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posted:9/6/2012
language:English
pages:13