Add GoTO Aug, 19 presentation

slides/highperf.slide

@@ -0,0 +1,203 @@
+High Performance Code in GO
+GoTO, August 2019
+Tags: GraphQL, API, GoLang, Postgres
+
+Vikram Rangnekar 
+https://twitter.com/dosco
+
+* About me
+
+Co-founder of *movremote.com* a platform to connect developers with Silicon Valley
+companies hiring remote.
+
+Previously worked on Platform, Frontend and Ads @ Linkedin building the distributed targeting and serving infrastructure behind Linkedin Ads.
+
+Also currently building Super Graph an open source instant GraphQL engine for Postgres and Rails. Written in GO
+
+MOV Remote
+.link https://movremote.com
+
+Super Graph
+.link https://supergraph.dev
+
+* Why does it matter?
+
+- Computer are not getting dramatically faster
+- Our software is getting slower
+- Demands on our software are increasing
+- Scale of internet poducts is accelerating
+- Faster = More money (For you)
+
+* What does high performance mean?
+
+- Code that runs fast (relative)
+- Minimizes I/O latency
+- Efficient in terms of GC
+
+
+  "Premature optimization is the root of all evil (or at least most of it) in programming." 
+  -- Donald Knuth
+
+  "Measure twice cut once"
+  -- Someone
+
+* Code that runs fast
+
+1. Algorithm choices
+2. Rewrite in GO
+3. Reuse Memory
+4. Parallelize I/O
+4. Keep it simple
+
+* Benchmarking
+
+* $ benchcmp bench.1 bench.2
+
+.image https://pbs.twimg.com/media/D8_uRFWU0AUdWkM?format=jpg&name=large _ 970
+
+* Howto benchmark
+
+Single threaded
+
+  func BenchmarkYourFunc(b *testing.B) {
+    for n := 0; n < b.N; n++ {
+      _, err := yourFunction(data)
+      ...
+    }
+  }
+
+Parallel
+
+  func BenchmarkYourFuncP(b *testing.B) {
+
+    b.RunParallel(func(pb *testing.PB) {
+      for pb.Next() {
+        _, err := yourFunction(data)
+        ...
+      }
+    })
+  }
+
+* Profileing Your Code
+
+  go test -bench=. -benchmem -memprofile mem.out -run=XXX
+  go tool pprof -cum mem.out
+
+Get a nice command line
+
+  pkg: github.com/dosco/super-graph/psql
+  BenchmarkCompile-8           	  100000	     15138 ns/op	    3553 B/op	      35 allocs/op
+  BenchmarkCompileParallel-8   	  300000	      4760 ns/op	    3583 B/op	      35 allocs/op
+  PASS
+  ok  	github.com/dosco/super-graph/psql	3.174s
+  Type: alloc_space
+  Time: Aug 21, 2019 at 11:56am (EDT)
+  Entering interactive mode (type "help" for commands, "o" for options)
+  (pprof)
+
+Powerful commands
+
+top, web, png, pdf, ... and more
+
+* Top - Shows you the top allocating functions
+
+  (pprof) top
+  Showing nodes accounting for 1.07GB, 77.92% of 1.37GB total
+  Showing top 10 nodes out of 34
+        flat  flat%   sum%        cum   cum%
+      0.01GB  0.89%  0.89%     1.11GB 80.77%  github.com/[...]/qcode.(*Compiler).Compile
+          0     0%  0.89%     1.02GB 74.22%  github.com/dosco/super-graph/
+      0.52GB 37.74% 38.63%     0.94GB 68.50%  github.com/[...]/qcode.(*Compiler).compileQuery
+      0.54GB 39.29% 77.92%     0.54GB 39.29%  github.com/dosco/super-graph/util.NewStack
+  
+Digging deeper
+
+  (pprof) top .compileQuery
+  focus=.compileQuery
+  Showing nodes accounting for 1006.59MB, 69.36% of 1451.18MB total
+  Showing top 10 nodes out of 26
+        flat  flat%   sum%        cum   cum%
+          0     0%     0%  1006.05MB 69.33%  github.com/[...]/qcode.(*Compiler).Compile
+    579.44MB 39.93% 39.93%  1006.05MB 69.33%  github.com/[...]/qcode.(*Compiler).compileQuery
+
+* Cool Graphs
+
+.image https://matoski.com/article/golang-profiling-flamegraphs/cpu-profile-graph-001.png 500 _
+
+* Reducing Allocations - Part 1
+
+Pre-allocate
+
+  m := make(map[string]someStruct{}, len(whatever))
+  mp := &m[i]
+
+Work with bytes if possible
+
+  inlineToLower(&value) instead of bytes.ToLower(value)
+
+Reuse Memory
+
+  var nodePool = sync.Pool{ 
+    New: func() interface{} { return new(Node) },
+  }
+
+Use Builders
+
+  var b strings.Builder
+  b.WriteString("hello "); 
+  b.WriteString("world")
+
+* Reducing Allocations - Part 2
+
+Use streaming (io.Reader and io.Writer)
+
+  r := strings.NewReader("some io.Reader stream to be read\n")
+
+  _, err := io.Copy(os.Stdout, r); 
+
+Allocate Together
+
+  type Node struct {
+    Children   []Child
+    childA     [5]Child
+  }
+  n := Node{}
+  n.Children = n.childA[:0]
+
+Use 'Append' functions
+
+	strconv.AppendInt(b10, 42, 10) instead of strconv.FormatInt(42, 10)
+
+* Reducing Allocations - Part 3
+
+Use 'unsafe' if you know what you're doing
+
+  func bytesToString(b []byte) string {
+    return *(*string)(unsafe.Pointer(&b))
+  }
+
+* Squeezing out more performance
+
+Avoid reflection use generators
+
+Inlined Assembly (Crazy)
+
+  // add.go
+  package main
+
+  import "fmt"
+
+  func add(x, y int64) int64
+
+  func main() {
+    fmt.Println(add(2, 3))
+  }
+
+  // add_amd64.s
+  TEXT ·add(SB),NOSPLIT,$0
+    MOVQ x+0(FP), BX
+    MOVQ y+8(FP), BP
+    ADDQ BP, BX
+    MOVQ BX, ret+16(FP)
+    RET
+

slides/overview.slide

@@ -3,7 +3,7 @@ Instant GraphQL API for Rails. Zero Code.
 Tags: GraphQL, API, GoLang, Postgres
 
 Vikram Rangnekar 
-https://twitter.com/@dosco
+https://twitter.com/dosco
 
 
 * Motivation

slides/whygraphql.slide

@@ -3,7 +3,7 @@ GraphQL is the future of APIs
 Tags: GraphQL, API, GoLang, Postgres
 
 Vikram Rangnekar 
-https://twitter.com/@dosco
+https://twitter.com/dosco
 
 * Trends, Why APIs are Important