Skip to content
master
Go to file
Code

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
bin
 
 
lib
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

README.md

PerfCounters

Experimental, do not use in production, could blow up your Rubies.

What

Read the CPU's performance counters from Ruby using perf_event_open(2).

Installation

$ gem install perf_counters

Usage

require 'perf_counters'
events = [
  Event::INSTRUCTIONS,
  Event::CPU_CYCLES,
  Event::CACHE_MISSES,
]
perf = PerfCounters::Measurement.new(
  exclude_kernel: true,
  events: events,
)
perf.start
# do something here
perf.stop
=> {:instructions=>3276, :cpu_cycles=>18651, :cache_misses=>24}

Sample Rack middleware in a Rails app

class PerformanceCountersRackMiddleware
  def initialize app
    @app = app
  end

  def call env
    events = [
      Event::INSTRUCTIONS,
      Event::CPU_CYCLES,
      Event::CACHE_MISSES,
      Event::CONTEXT_SWITCHES,
      Event::BUS_CYCLES,
      Event::PAGE_FAULTS_MIN,
    ]
    perf_data = PerfCounters.measure(exclude_kernel: true, events: events) do
      @status, @headers, @response = @app.call(env)
    end

    Rails.logger.info "#{perf_data}"

    [@status, @headers, @response]
  end
end

For 2 request it outputs something like:

{:instructions=>93930165, :cpu_cycles=>69263494, :cache_misses=>101678, :context_switches=>0, :bus_cycles=>2663999, :page_faults_min=>216}
[...]
Completed 200 OK in 71ms (Views: 54.7ms)


{:instructions=>93984918, :cpu_cycles=>74644389, :cache_misses=>116050, :context_switches=>0, :bus_cycles=>2870920, :page_faults_min=>246}
[...]
Completed 200 OK in 50ms (Views: 38.2ms)

Contributing

Requirements

A modern Linux machine (unfortunately, most VMs don't virtualize perf counters) with perf installed.

Install

$ bin/setup

Compile

$ rake compile

Run tests

$ rake [test]

About

Ruby gem to access the CPU performance counters (PMU) using perf_event_open(2)

Topics

Resources

License

Releases

No releases published

Packages

No packages published
You can’t perform that action at this time.