cpi-breakdown-model

CBM

CBM is a performance analysis tool for system-wide profiling based on CPI - Cycles per Instruction - Breakdown Model. It runs Oprofile Linux tool to collect PMU counters and calcutates CPI metrics on Power Platform. The tool helps profiling complex workloads and evaluating performance.

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               CPI Breakdown Model, a performance tool
          https://github.com/rafaelfolco/cpi-breakdown-model

Requirements

• oprofile (system-wide profiler for Linux systems)
• python (2.7)

Run

Run CBM (as root) for a given amount of time:

    # python cbm.py --duration=60 --rotation=5

This will run CBM for 60 minutes collecting 5 samples of each performance counter. Then open the HTML report html/cpi.html in a browser. You can start a simple HTTP server by running:

    # python -m SimpleHTTPServer

CBM HTML report will be available at: http://<hostname>:8000/html/cpi.html

Debug

Run CBM with --debug:

    # python cbm.py --duration=60 --rotation=5 --debug

Methodology

Performance Monitoring Units (PMU) are counted during the specified duration time. These counters are collected by groups, divided into time slices within the overall runtime.

  |-g1-g2-g3-g4-g5-|
  |--- runtime ----|

For long runs, its is possible to collect multiple samples in order to get a more precise performance analysis of the running workload over time.

  |-g1-g2-g3-g4-g5-|-g1-g2-g3-g4-g5-|...|-g1-g2-g3-g4-g5-|
  |     sample 1   |     sample 2   |...|    sample N    |
  |---------------------- runtime -----------------------|

CBM sums all samples from each group for every counter. CPI metrics are finally calculated for each group of counters.

TODOs

• Write unit tests
• Fix RUN_CYCLES: sum of Breakdown 1 metrics is not actually 100%
• Show description for metrics and counters from breakdown table