From 2417a6b7603524dc5cd30d29b153f91024b9443d Mon Sep 17 00:00:00 2001
From: Mitja Felicijan <mitja.felicijan@gmail.com>
Date: Wed, 1 Nov 2023 22:54:27 +0100
Subject: Move to Jekyll

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+---
+title: Golang profiling simplified
+permalink: /golang-profiling-simplified.html
+date: 2017-03-07T12:00:00+02:00
+layout: post
+type: post
+draft: false
+---
+
+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.
+
+Nevertheless, after searching and experimenting I have found a solution that
+works for me and probably should also for you.
+
+## Where are my pprof files?
+
+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.
+
+## Why is my CPU profile empty?
+
+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.
+
+## Profiling
+
+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.
+
+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.
+
+### Memory profiling
+
+```go
+package main
+
+import (
+  "fmt"
+  "time"
+  "github.com/pkg/profile"
+)
+
+func dummy_benchmark() {
+
+  fmt.Println("first set ...")
+  for i := 0; i < 918231333; i++ {
+    i *= 2
+    i /= 2
+  }
+
+  <-time.After(time.Second*3)
+
+  fmt.Println("sencond set ...")
+  for i := 0; i < 9182312232; i++ {
+    i *= 2
+    i /= 2
+  }
+}
+
+func main() {
+  defer profile.Start(profile.MemProfile, profile.ProfilePath("."), profile.NoShutdownHook).Stop()
+  dummy_benchmark()
+}
+```
+
+### CPU profiling
+
+```go
+package main
+
+import (
+  "fmt"
+  "time"
+  "github.com/pkg/profile"
+)
+
+func dummy_benchmark() {
+
+  fmt.Println("first set ...")
+  for i := 0; i < 918231333; i++ {
+    i *= 2
+    i /= 2
+  }
+
+  <-time.After(time.Second*3)
+
+  fmt.Println("sencond set ...")
+  for i := 0; i < 9182312232; i++ {
+    i *= 2
+    i /= 2
+  }
+}
+
+func main() {
+  defer profile.Start(profile.CPUProfile, profile.ProfilePath("."), profile.NoShutdownHook).Stop()
+  dummy_benchmark()
+}
+```
+
+### Generating profiling reports
+
+```bash
+# memory profiling
+go build mem.go
+./mem
+go tool pprof -pdf ./mem mem.pprof > mem.pdf
+
+# cpu profiling
+go build cpu.go
+./cpu
+go tool pprof -pdf ./cpu cpu.pprof > cpu.pdf
+```
+
+This will generate PDF document with visualized profile.
+
+- [Memory PDF profile example](/assets/posts/go-profiling/golang-profiling-mem.pdf)
+- [CPU PDF profile example](/assets/posts/go-profiling/golang-profiling-cpu.pdf)
+
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