tips and tricks

Author: ysoldak

content/docs/guides/tips-n-tricks.md

@@ -0,0 +1,69 @@
+---
+title: "Tips, Tricks and Gotchas"
+weight: 4
+description: |
+  Tips and tricks for small places.
+  How to write efficient embedded code and avoid common mistakes.
+---
+
+## Ensure Concurrency
+
+TinyGo code runs on a single core, in a single thread (think `GOMAXPROCS=1`).
+Since scheduling in TinyGo is [cooperative](https://en.wikipedia.org/wiki/Cooperative_multitasking), a goroutine that never does IO or other blocking calls (f.ex. `time.Sleep()`) will lock the single available thread only for itself and never allow other goroutines to execute. In such cases, you can use `runtime.Gosched()` as a workaround.
+
+```
+package main
+
+import (
+    "fmt"
+    "time"
+    "sync/atomic"
+    "runtime"
+)
+
+func main() {
+
+    var ops uint64 = 0
+    for i := 0; i < 50; i++ {
+        go func() {
+            for {
+                atomic.AddUint64(&ops, 1)
+                runtime.Gosched()
+            }
+        }()
+    }
+
+    time.Sleep(time.Second)
+
+    opsFinal := atomic.LoadUint64(&ops)
+    fmt.Println("ops:", opsFinal)
+}
+```
+
+## Save Memory
+
+Use the fact [slices are descriptors of array segments](https://go.dev/blog/slices-intro#slice-internals) to save memory and avoid unnecessary allocations.
+Allocate once an array of maximum size you ever need and slice it in your methods to the required sizes as you go.
+
+```
+type MyType struct {
+    // ...other fields
+    buf [6]byte
+}
+
+func (t *MyType) SomeMethod() {
+    tmpBuf := t.buf[:2] // this method needs a buffer of size 2
+    // ... use the buffer
+}
+```
+
+You may even find yourself having two or more slices pointing at diferent regions of the same array simultaneously, if you are careful.
+
+```
+buf1 := t.buf[:2]
+buf2 := t.buf[2:6]
+```
+
+For more recipes on how to avoid or minimize allocations while working with slices, please see [additional tricks](https://github.com/golang/go/wiki/SliceTricks#additional-tricks) section of [slice tricks](https://github.com/golang/go/wiki/SliceTricks) page.
+
+Familiarize yourself with [heap allocation concept](../concepts/compiler-internals/heap-allocation.md) and use it to your advantage.