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<!doctype html><html lang=en-us><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><link href="data:image/x-icon;base64,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" rel=icon type=image/x-icon><title>Golang profiling simplified</title><meta name=description content="Many posts have been written regarding profiling in Golang and I haven’t foundproper tutorial regarding this."><link rel=alternate type=application/rss+xml title="Mitja Felicijan's posts" href=https://mitjafelicijan.com/index.xml><link rel=alternate type=application/rss+xml title="Mitja Felicijan's notes" href=https://mitjafelicijan.com/notes.xml><style>body{padding:1rem;max-width:760px;background:#fff;font-family:times new roman,Times,serif;line-height:1.35rem}hr{margin-block-start:1.5rem}h1,h2,h3{line-height:initial}footer{margin-block-start:3rem}table{max-width:100%;border-collapse:separate;border-spacing:2px;border:1px solid #000;border-left:1px solid #999;border-top:1px solid #999}blockquote{font-style:italic}table thead{background:#eee}td,th{border:1px solid #000;padding:4px;border-right:1px solid #999;border-bottom:1px solid #999;text-align:left}pre{text-wrap:nowrap;overflow-x:auto;margin-block-start:1.5rem;margin-block-end:1.5rem;padding:.5rem 0;border-top:1px solid #000;border-bottom:1px solid #000}pre code{line-height:1.3em}pre,code,pre *,code *{font-family:monospace;font-size:initial!important}img,video,audio{max-width:100%}header{display:flex;flex-direction:row;gap:3rem}nav{display:flex;gap:.75rem}.pstatus-orange{background:gold}.pstatus-green{background:#9acd32}.pstatus-red{background:#cd5c5c}@media only screen and (max-width:600px){header{flex-direction:column;gap:1rem}a{word-wrap:break-word}}</style><header><nav class=main><a href=/>Home</a>
<a href=https://git.mitjafelicijan.com/ target=_blank>Git</a>
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<a href=/index.xml target=_blank>RSS</a></nav></header><main><div><h1>Golang profiling simplified</h1><p>Mar 7, 2017<div><p>Many posts have been written regarding profiling in Golang and I haven’t found
proper tutorial regarding this. Almost all of them are missing some part of
important information and it gets pretty frustrating when you have a deadline
and are not finding simple distilled solution.<p>Nevertheless, after searching and experimenting I have found a solution that
works for me and probably should also for you.<h2 id=where-are-my-pprof-files>Where are my pprof files?</h2><p>By default pprof files are generated in /tmp/ folder. You can override folder
where this files are generated programmatically in your golang code as we will
see below in example.<h2 id=why-is-my-cpu-profile-empty>Why is my CPU profile empty?</h2><p>I have found out that sometimes CPU profile is empty because program was not
executing long enough. Programs, that execute too quickly don’t produce pprof
file in my cases. Well, file is generated but only contains 4KB of information.<h2 id=profiling>Profiling</h2><p>As you can see from examples we are executing dummy_benchmark functions to
ensure some sort of execution. Memory profiling can be done without such a
“complex” function. But CPU profiling needs it.<p>Both memory and CPU profiling examples are almost the same. Only parameters in
main function when calling profile.Start are different. When we set
profile.ProfilePath(“.”) we tell profiler to store pprof files in the same
folder as our program.<h3 id=memory-profiling>Memory profiling</h3><pre tabindex=0 style=background-color:#fff><code><span style=display:flex><span><span style=color:#00f>package</span> main
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:#00f>import</span> (
</span></span><span style=display:flex><span> <span style=color:#a31515>"fmt"</span>
</span></span><span style=display:flex><span> <span style=color:#a31515>"time"</span>
</span></span><span style=display:flex><span> <span style=color:#a31515>"github.com/pkg/profile"</span>
</span></span><span style=display:flex><span>)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:#00f>func</span> dummy_benchmark() {
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span> fmt.Println(<span style=color:#a31515>"first set ..."</span>)
</span></span><span style=display:flex><span> <span style=color:#00f>for</span> i := 0; i < 918231333; i++ {
</span></span><span style=display:flex><span> i *= 2
</span></span><span style=display:flex><span> i /= 2
</span></span><span style=display:flex><span> }
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span> <-time.After(time.Second*3)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span> fmt.Println(<span style=color:#a31515>"sencond set ..."</span>)
</span></span><span style=display:flex><span> <span style=color:#00f>for</span> i := 0; i < 9182312232; i++ {
</span></span><span style=display:flex><span> i *= 2
</span></span><span style=display:flex><span> i /= 2
</span></span><span style=display:flex><span> }
</span></span><span style=display:flex><span>}
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:#00f>func</span> main() {
</span></span><span style=display:flex><span> <span style=color:#00f>defer</span> profile.Start(profile.MemProfile, profile.ProfilePath(<span style=color:#a31515>"."</span>), profile.NoShutdownHook).Stop()
</span></span><span style=display:flex><span> dummy_benchmark()
</span></span><span style=display:flex><span>}
</span></span></code></pre><h3 id=cpu-profiling>CPU profiling</h3><pre tabindex=0 style=background-color:#fff><code><span style=display:flex><span><span style=color:#00f>package</span> main
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:#00f>import</span> (
</span></span><span style=display:flex><span> <span style=color:#a31515>"fmt"</span>
</span></span><span style=display:flex><span> <span style=color:#a31515>"time"</span>
</span></span><span style=display:flex><span> <span style=color:#a31515>"github.com/pkg/profile"</span>
</span></span><span style=display:flex><span>)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:#00f>func</span> dummy_benchmark() {
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span> fmt.Println(<span style=color:#a31515>"first set ..."</span>)
</span></span><span style=display:flex><span> <span style=color:#00f>for</span> i := 0; i < 918231333; i++ {
</span></span><span style=display:flex><span> i *= 2
</span></span><span style=display:flex><span> i /= 2
</span></span><span style=display:flex><span> }
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span> <-time.After(time.Second*3)
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span> fmt.Println(<span style=color:#a31515>"sencond set ..."</span>)
</span></span><span style=display:flex><span> <span style=color:#00f>for</span> i := 0; i < 9182312232; i++ {
</span></span><span style=display:flex><span> i *= 2
</span></span><span style=display:flex><span> i /= 2
</span></span><span style=display:flex><span> }
</span></span><span style=display:flex><span>}
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:#00f>func</span> main() {
</span></span><span style=display:flex><span> <span style=color:#00f>defer</span> profile.Start(profile.CPUProfile, profile.ProfilePath(<span style=color:#a31515>"."</span>), profile.NoShutdownHook).Stop()
</span></span><span style=display:flex><span> dummy_benchmark()
</span></span><span style=display:flex><span>}
</span></span></code></pre><h3 id=generating-profiling-reports>Generating profiling reports</h3><pre tabindex=0 style=background-color:#fff><code><span style=display:flex><span><span style=color:green># memory profiling</span>
</span></span><span style=display:flex><span>go build mem.go
</span></span><span style=display:flex><span>./mem
</span></span><span style=display:flex><span>go tool pprof -pdf ./mem mem.pprof > mem.pdf
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:green># cpu profiling</span>
</span></span><span style=display:flex><span>go build cpu.go
</span></span><span style=display:flex><span>./cpu
</span></span><span style=display:flex><span>go tool pprof -pdf ./cpu cpu.pprof > cpu.pdf
</span></span></code></pre><p>This will generate PDF document with visualized profile.<ul><li><a href=/assets/go-profiling/golang-profiling-mem.pdf>Memory PDF profile example</a><li><a href=/assets/go-profiling/golang-profiling-cpu.pdf>CPU PDF profile example</a></ul></div></div></main><footer><hr><div><h3>Want to comment or have something to add?</h3>You can write me an email at
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