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Optimizing a sample Linux system

In this study, Akamas is tasked with the optimization of Linux1, a Linux-based system (Ubuntu). The study's goal is to maximize the throughput of the computations of the Sysbench CPU benchmark.
Sysbench is a suite of benchmarks for CPU, file system, memory, threads, etc… typically used for testing the performance of databases.
System1 comes with a Node Exporter that collects system metrics that Akamas consumes through a Prometheus provider. Concerning Sysbench metrics, The study uses the CSV provider to make them available to Akamas.
The study uses Sysbench to execute a performance test against System1.

Telemetry

  1. 1.
    Setup a Prometheus and a Node Exporter to monitor the System
  2. 2.
    Install the Prometheus provider
  3. 3.
    Create a provider instance:
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provider: "Prometheus"
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config:
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address: "linux1" # address of the Prometheus of system1
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port: 9090 # port of the Prometheus of system1
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component: "linux1-linux"
4. Install the CSV File provider.
5. Create a provider instance:
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provider: "CSV"
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config:
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address: "linux1"
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authType: "password"
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username: "ubuntu"
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auth: "[INSERT PASSWORD HERE]"
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protocol: scp
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remoteFilePattern: "/home/ubuntu/benchmark_log.csv" # the remote path of the csv with the metrics of the benchmark
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componentColumn: "component" # which column of the csv should contain the name of the component
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csvFormat: "horizontal"
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metrics:
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- metric: "throughput"
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datasourceMetric: "events_per_second"

Workflow

The study uses a four-task workflow to test System1 with a new configuration:
  1. 1.
    Task Configure OS, which leverages the LinuxConfigurator operator to apply a new set of Linux configuration parameters
  2. 2.
    Task Start benchmark, which leverages the Executor operator to launch the benchmark
The following YAML file represents the complete workflow definition:
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name: "workflow for linux 1"
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tasks
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- name: "Configure OS"
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operator: "LinuxConfigurator"
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arguments:
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component: linux1-linux
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- name: "Start benchmark"
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operator: "Executor"
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arguments:
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command: "bash /home/ubuntu/benchmark.sh"
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host:
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hostname: "linux1"
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username: "ubuntu"
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password: "[INSERT_HERE_PASSWORD]"

System

Within Akamas, System1 is modeled by a system of two components:
  • system1-linux, which represents the actual Linux system with its metrics and parameters and is of type Ubuntu 16.04
  • system1-bench, which represents the Sysbench with its metrics and is of type Sysbench
The following YAML file represents the definition of the Sysbench component type:
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name: "Sysbench"
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description: "A component-type for Sysbench"
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metrics:
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- "throughput" # only one metric

Study

  • Goal: minimize the throughput of the benchmark
  • Windowing: take the default (compute the score for the entire duration of a trial)
  • Parameters selection: select only CPU scheduling parameters
  • Metrics selection: select only the throughput of the benchmark
  • Trials: 3
  • Steps: one baseline and one optimize
The following YAML file represents the definition of the study:
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system: "system for linux1"
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workflow: "workflow ofr linux1"
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name: "linux optimization with sysbench"
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description: "Optimizing an Ubuntu instance with a CPU intensive benchmark: sysbench"
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goal:
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objective: minimize
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function:
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formula: "linux1-benchmark.throughput"
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metricsSelection:
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- "linux1-benchmark.throughput"
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parametersSelection:
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- name: "linux1-linux.os_cpuSchedMinGranularity"
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- name: "linux1-linux.os_cpuSchedWakeupGranularity"
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- name: "linux1-linux.os_CPUSchedMigrationCost"
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- name: "linux1-linux.os_CPUSchedChildRunsFirst"
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- name: "linux1-linux.os_CPUSchedLatency"
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- name: "linux1-linux.os_CPUSchedAutogroupEnabled"
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- name: "linux1-linux.os_CPUSchedNrMigrate"
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numberOfTrials: 3
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steps:
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- name: "baseline"
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type: "baseline"
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values:
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linux1-linux.os_cpuSchedMinGranularity: 2250000
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linux1-linux.os_cpuSchedWakeupGranularity: 3000000
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linux1-linux.os_CPUSchedMigrationCost: 500000
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linux1-linux.os_CPUSchedChildRunsFirst: 0
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linux1-linux.os_CPUSchedLatency: 18000000
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linux1-linux.os_CPUSchedAutogroupEnabled: 1
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linux1-linux.os_CPUSchedNrMigrate: 32
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- name: "optimization"
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type: "optimize"
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numberOfExperiments: 99
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maxFailedExperiments: 25