05-profiling

README

Profiling Code

We can use the go tooling in conjunction with the Graph Visualization Tools and Ghostscript. These tools will allow us to graph the profiles we create.

Note: Unless you are running OS X El Capitan, profiling on the Mac is broken. This post talks about how to hack to OS X Kernel to make it work.
http://research.swtch.com/macpprof
https://godoc.org/rsc.io/pprof_mac_fix

Installing Tools

download files

Dave Cheney's Profile Package

go get Dave Cheney's profiling package. He has done a nice job abstracting all the boilerplate code required. If you are interested in understanding how to do this without the profile package, read this (http://saml.rilspace.org/profiling-and-creating-call-graphs-for-go-programs-with-go-tool-pprof)

go get github.com/davecheney/profile

Graph Visualization Tools

Download the package for your target OS/Arch: http://www.graphviz.org/Download.php

Ghostscript

This is not an easy step for Mac users since there is no prebuilt distribution.

Download and uncompress the source code: http://ghostscript.com/download/gsdnld.html

./configure
make
sudo make install

Code Changes

We need to make some changes to main to get the profiling data we need.

import "github.com/davecheney/profile"

// main is the entry point for the application.
func main() {
	cfg := profile.Config{
		MemProfile:     true,
		CPUProfile:     true,
		ProfilePath:    ".",  // store profiles in current directory
		NoShutdownHook: true, // do not hook SIGINT
	}

	// p.Stop() must be called before the program exits to
	// ensure profiling information is written to disk.
	p := profile.Start(&cfg)
	defer p.Stop()

	. . .
}

Running and Creating Profile Graphs

Build and run the service:
	go build
	./05-profiling

In a separate terminal generate requests:
	while true && do curl http://localhost:6060/english && done
	<control> C

Generate the call graphs:
	go tool pprof --pdf ./05-profiling cpu.pprof > cpugraph.pdf
	go tool pprof --pdf ./05-profiling mem.pprof > memgraph.pdf

See all the options:
	go tool pprof -h

HTTP Runtime Profile Graphs

Build and run the service:
	go build
	./05-profiling

In a separate terminal generate requests:
	while true && do curl http://localhost:6060/english && done

In a separate terminal run a pprof tool:
	go tool pprof http://localhost:6060/debug/pprof/heap
	go tool pprof http://localhost:6060/debug/pprof/profile
	go tool pprof http://localhost:6060/debug/pprof/block

Play with the different commands:
	go tool pprof -help

Links

http://golang.org/blog/profiling-go-programs

http://golang.org/pkg/runtime/pprof/

https://golang.org/pkg/net/http/pprof/

https://godoc.org/rsc.io/pprof_mac_fix

Code Review

HTTP Service (Go Playground)

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All material is licensed under the Apache License Version 2.0, January 2004.

Documentation

Overview

Sample program to show how profiling works. This is the base code. Use the readme for changes needed to be made to the code.