Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
You, latency and profiling @ GopherCon India 2017
Search
Filippo Valsorda
February 25, 2017
Programming
13
4.1k
You, latency and profiling @ GopherCon India 2017
Filippo Valsorda
February 25, 2017
Tweet
Share
More Decks by Filippo Valsorda
See All by Filippo Valsorda
Asynchronous networking @ GopherCon 2018
filosottile
3
2.1k
Le note cifrate di Antonio Marzi
filosottile
1
410
Why cgo is slow @ CapitalGo 2018
filosottile
2
4.6k
Squeezing a key through a carry bit @ 34c3
filosottile
0
1.7k
Calling Rust from Go, without cgo @ GothamGo 2017
filosottile
1
2.7k
You, latency and profiling @ GolangUK 2017
filosottile
0
1.2k
Encrypting the Internet with Go @ GopherCon 2017
filosottile
9
2.6k
TLS 1.3 @ 33c3
filosottile
4
6.9k
Stealing Bitcoin With Math - HOPE XI
filosottile
13
30k
Other Decks in Programming
See All in Programming
ぬるぬる動かせ! Riveでアニメーション実装🐾
kno3a87
1
230
go test -json そして testing.T.Attr / Kyoto.go #63
utgwkk
3
310
はじめてのMaterial3 Expressive
ym223
2
890
パッケージ設計の黒魔術/Kyoto.go#63
lufia
3
440
AWS発のAIエディタKiroを使ってみた
iriikeita
1
190
アプリの "かわいい" を支えるアニメーションツールRiveについて
uetyo
0
270
アセットのコンパイルについて
ojun9
0
130
請來的 AI Agent 同事們在寫程式時,怎麼用 pytest 去除各種幻想與盲點
keitheis
0
120
Design Foundational Data Engineering Observability
sucitw
3
200
ProxyによるWindow間RPC機構の構築
syumai
3
1.2k
「手軽で便利」に潜む罠。 Popover API を WCAG 2.2の視点で安全に使うには
taitotnk
0
870
AI時代のUIはどこへ行く?
yusukebe
18
9k
Featured
See All Featured
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
507
140k
Gamification - CAS2011
davidbonilla
81
5.4k
The Psychology of Web Performance [Beyond Tellerrand 2023]
tammyeverts
49
3k
Fireside Chat
paigeccino
39
3.6k
GitHub's CSS Performance
jonrohan
1032
460k
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
656
61k
Documentation Writing (for coders)
carmenintech
74
5k
Into the Great Unknown - MozCon
thekraken
40
2k
KATA
mclloyd
32
14k
Unsuck your backbone
ammeep
671
58k
Large-scale JavaScript Application Architecture
addyosmani
513
110k
StorybookのUI Testing Handbookを読んだ
zakiyama
31
6.1k
Transcript
You, latency and profiling Filippo Valsorda — @FiloSottile
What is fast?
A fast hash… … can hash many MB per second
A fast regex… … can process many MB/s
A fast database… … can store many GB per second
A fast database… … can store many GB per second
… or replies to queries in a few milliseconds
A fast website… … can handle many requests at the
same time … or loads in a few milliseconds
A fast API… … can handle many clients at the
same time … or answers in a few milliseconds
Fast is… Throughput and Latency
CPU profiling -cpuprofile /debug/pprof/profile
CPU profiling SIGPROF
runtime/proc.go
CPU profiling http.Handler 1 Running on CPU http.Handler 2 I/O
I/O http.Handler 3 I/O http.Handler 4 I/O
CPU profiling Running on CPU I/O I/O I/O I/O http.Handler
1 http.Handler 2 http.Handler 3 http.Handler 4
CPU profiling I/O Observed latency http.Handler 1
func Write(data []byte) { for i := 0; i <
50; i++ { tmpfile, _ := ioutil.TempFile("", "ex") defer os.Remove(tmpfile.Name()) _, err = tmpfile.Write(data) tmpfile.Close() } } func Hash(data []byte) { for i := 0; i < 50; i++ { sha256.Sum256(data) } }
$ time curl http://127.0.0.1:12345/hash-and-write 9.831 total go tool pprof -web
slowserver cpu.pprof
None
$ time curl http://127.0.0.1:12345/hash-and-write 9.831 total $ time
curl http://127.0.0.1:12345/write-no-hash 7.692 total
Latency is not all about CPU
CPU profiling is for throughput The tracer is for latency
$ time curl http://127.0.0.1:12345/write-no-hash 7.692 total go tool trace -pprof=syscall
trace.out > syscall.pprof go tool pprof -web syscall.pprof
None
The tracer Detailed nanosecond-level log of execution events: • goroutine
scheduling, blocking • syscalls, network, I/O • garbage collection
The tracer • log files are BIG • 25% overhead
(after Go 1.7) • symbols are embedded (Go 1.7)
Trace vs. profile • Full event context • Goroutine metadata
and history • Discrete events, not samples
The tracer import "runtime/trace" import "net/http/pprof" /debug/pprof/trace?seconds=5
None
go tool trace -pprof=TYPE trace.out Supported profile types are: -
net: network blocking profile - sync: synchronization blocking profile - syscall: syscall blocking profile - sched: scheduler latency profile
go tool trace -pprof=syscall trace.out > syscall.pprof go tool pprof
-web syscall.pprof
go tool trace -pprof=syscall trace.out > syscall.pprof go-torch -b syscall.pprof
&& open torch.svg
None
None
-pprof=syscall func Write(data []byte) { for i := 0; i
< 50; i++ { tmpfile, _ := ioutil.TempFile("", "ex") defer os.Remove(tmpfile.Name()) _, err = tmpfile.Write(data) tmpfile.Close() } }
-pprof=sync // Block waits on a channel func Block() {
<-time.After(1 * time.Second) }
-pprof=sync
-pprof=sync
-pprof=net func Download() []byte { r, err := http.Get("https://golang.org/doc/go1.8") body,
err := ioutil.ReadAll(r.Body) r.Body.Close() return body }
-pprof=net
-pprof=net
None
Writing our own profile prof := make(map[uint64]pprof.Record) for _, ev
:= range events { if ev.Type != trace.EvGoBlockNet { continue } rec := prof[ev.StkID] rec.Stk = ev.Stk rec.N++ rec.Time += ev.Link.Ts - ev.Ts prof[ev.StkID] = rec } pprof.BuildProfile(prof).Write(os.Stdout)
var childG = make(map[uint64]struct{}) var lastGLen int for { for
_, ev := range events { if ev.Type != trace.EvGoCreate { continue } if _, ok := childG[ev.G]; !ok && !filterStack(ev.Stk, re) { continue } childG[ev.Args[0]] = struct{}{} } if len(childG) == lastGLen { break } lastGLen = len(childG) }
if _, ok := childG[ev.G]; !ok && !filterStack(ev.Stk, re) {
continue }
tracefocus tracefocus -filter=ServeHTTP trace.out > net.pprof github.com/FiloSottile/tracetools
None
None
Build more tools! • Focus on goroutine number • Aggregate
all blocking types • Visualizations • …
tracehist tracehist -filter=Close trace.out github.com/FiloSottile/tracetools
None
Build more tools! Profile latency!
Questions? Filippo Valsorda @FiloSottile filippo@cloudflare.com