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Last active May 16, 2022 07:16
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Perfchat 15 May 2022

Perfchat 15 May 2022 Show Notes

News by Denis

General Disussion

  • Mark's blog post
  • Performance myth 5 - tool experise (perf,vtune,jmeter...) is not highly corrolated with performance engineering skill.
  • Use NIC timestamps - bpftrace - use link shims to intercept system calls without need for administrator privlidges,
  • Myth 4 on memory usage - memory contoller overload matters, not just total RAM. pcm-memory intel_RTD
  • Experiment with pinning cores and keeping IO caches hot to lower latency of L3 misses.
  • Myth 3 - Sampling Profilers Work Great for Multithreaded Apps - need tool like coz.
  • Myth 2 - CPU Clock Speed Is Paramount - hasn't been informative for years.
  • Myth 1 - Big O Complexity == Performance - only a factor for large problem sizes - cache oblivious scaling more important.
  • Denis' big 5 - not knowing the application stack - blindly relying on big O - blindly optimizing - creating bad benchmarks
  • Algorithms 4th Edition
  • x/y/z (t) plots What is the chance of X at timescale T experiencing a fault rate Y for Z time?
  • Look at CPU pipeline - much wider/deeper.
  • Hacking QEMU
  • Abusing SOUPER to slow down code like COZ?
  • egraphs for superoptimization and modeling.
  • https://github.com/opcm/pcm - https://github.com/influxdata/telegraf/blob/master/plugins/inputs/intel_rdt/README.md
  • Tracing with qemu
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