2nd/10_Wiki/Topic_Programming/Coding/Native_Perf_Tracing_Systrace.md

id, title, category, status, source_trust_level, verification_status, created_at, updated_at, tags, tech_stack, applied_in, aliases

id	title	category	status	source_trust_level	verification_status	created_at	updated_at	tags	tech_stack	applied_in	aliases
native-perf-tracing-systrace	Native Perf Tracing — Systrace / Instruments / Perfetto	Coding	draft	B	conceptual	2026-05-09	2026-05-09	native performance systrace perfetto instruments vibe-coding	language applicable_to Swift / Kotlin iOS Android		Systrace Perfetto Instruments Time Profiler frame timing trace

Native Perf Tracing

Frame drop / startup 느림 / scroll jank 분석 = trace tool. Android: Perfetto / Systrace. iOS: Instruments (Time Profiler / SwiftUI / Animation Hitches). Custom span 으로 본인 코드도 표시.

📖 핵심 개념

• Frame budget: 60fps = 16.6ms / 120fps = 8.3ms.
• Jank: budget 초과 = 사용자 보임.
• Trace: 시간축 위 함수 실행 그래프.
• Custom span: 라이브러리 / 본인 함수 표시.

💻 코드 패턴

Android — Perfetto (modern)

# Android Studio: Profiler → System Trace
# 또는 명령행:
adb shell perfetto --txt -c - --out /data/misc/perfetto-traces/trace -t 10s sched freq idle am wm gfx view binder_driver hal dalvik camera input res memory <<< ''

Custom trace section (Android)

import androidx.tracing.Trace

Trace.beginSection("loadHomeFeed")
val items = repo.loadFeed()
Trace.endSection()

// 또는 inline
Trace.beginAsyncSection("download:image:42", 42)
download(url) { Trace.endAsyncSection("download:image:42", 42) }

iOS — Instruments

Xcode → Product → Profile (⌘I) →
- Time Profiler: 시간 소요 함수
- Animation Hitches: 60fps 깬 frame
- SwiftUI: View 재계산
- Network: 요청 latency
- Allocations: 메모리

iOS — os_signpost (custom span)

import os.signpost

let log = OSLog(subsystem: "com.app", category: .pointsOfInterest)
let id = OSSignpostID(log: log)

os_signpost(.begin, log: log, name: "loadFeed", signpostID: id)
let items = await loadFeed()
os_signpost(.end, log: log, name: "loadFeed", signpostID: id)

Instruments → os_signpost instrument 추가하면 timeline 에 보임.

Frame timing (iOS)

let displayLink = CADisplayLink(target: self, selector: #selector(tick))
displayLink.add(to: .main, forMode: .common)

@objc func tick(_ dl: CADisplayLink) {
    let frameDuration = dl.targetTimestamp - dl.timestamp
    if frameDuration > 1.0 / 60.0 + 0.005 { print("hitch") }
}

Frame timing (Android)

Choreographer.getInstance().postFrameCallback(object : FrameCallback {
    var last = 0L
    override fun doFrame(now: Long) {
        if (last > 0) {
            val ms = (now - last) / 1_000_000
            if (ms > 16) Log.d("frame", "jank $ms ms")
        }
        last = now
        Choreographer.getInstance().postFrameCallback(this)
    }
})

App startup tracing

// AndroidX Startup Initializer 또는 manual
class App : Application() {
    override fun onCreate() {
        Trace.beginSection("App.onCreate")
        super.onCreate()
        // ...
        Trace.endSection()
    }
}

🤔 의사결정 기준

분석 대상	도구
Scroll jank	Systrace/Perfetto + Choreographer (Android) / Instruments Animation Hitches (iOS)
Cold startup	Systrace boot to firstFrame / iOS Launch Time
함수 hot path	Time Profiler (iOS) / CPU Profiler (Android)
사용자 본인 함수 표시	Trace.beginSection / os_signpost
네트워크 latency	Charles / 본인 SDK observability

❌ 안티패턴

• Trace section 안 닫음: timeline 깨짐.
• Profile build 안 씀: debug 는 느림 — release 또는 profile build 사용.
• profile 상태 의존: profiler attach 자체가 영향. 상대 비교만.
• 시작 측정 — emulator 만: 실기와 다름.
• 로그로 시간 측정: I/O 자체가 시간. 표시 적은 trace API.
• 첫 측정만 보기: warm-up 필요. 5번 평균.

🤖 LLM 활용 힌트

• iOS = os_signpost + Instruments. Android = Trace + Perfetto.
• Frame budget 16.6ms 기준 비교.

🔗 관련 문서

• Native_Memory_Profiling
• Native_ANR_Freeze_Debugging
• Native_Battery_Network_Profiling