mohitmishra786/low-level-dev-skills

heaptrack

heaptrack memory profiler skill for Linux.

ソースを見る

使い方

  1. インストールコマンドをコピーし、自分の環境へ導入する前にソースを確認します。
  2. 必要なツール、認証情報、対応環境を原文で確認します。
  3. 入力と成果物を指定し、出力を資料と照合します。
npx skills add https://github.com/mohitmishra786/low-level-dev-skills --skill heaptrack

開始前の確認

  • 導入にはモデル契約、API枠、ファイルへのアクセス許可は含まれません。
  • スター数や導入数は活動の指標であり、独立した品質・安全性試験ではありません。
リポジトリの原文

見出し、例、コード、表、リンク、参照画像を含む原文を表示しています。

heaptrack

Purpose

Guide agents through heaptrack for heap allocation profiling on Linux: recording allocation traces, analysing with heaptrack_print, identifying leaks and hotspots, and comparing runs.

Triggers

  • "How do I find memory allocation hotspots in my C++ program?"
  • "My program uses too much memory — how do I find where?"
  • "How do I use heaptrack to detect memory leaks?"
  • "What is heaptrack and how does it differ from Valgrind massif?"
  • "How do I compare memory usage between two program versions?"
  • "heaptrack_print output — how do I interpret it?"

Workflow

1. Installation

bash
# Ubuntu/Debian
sudo apt-get install heaptrack heaptrack-gui

# Fedora
sudo dnf install heaptrack

# Arch
sudo pacman -S heaptrack

# Build from source
git clone https://github.com/KDE/heaptrack.git
cmake -S heaptrack -B heaptrack-build -DCMAKE_BUILD_TYPE=Release
cmake --build heaptrack-build -j$(nproc)

2. Basic usage

bash
# Profile a program (generates heaptrack.<prog>.<pid>.zst)
heaptrack ./myapp arg1 arg2

# Attach to running process
heaptrack --pid 12345

# Analyse the trace file
heaptrack_print heaptrack.myapp.12345.zst

# GUI analysis (if heaptrack-gui installed)
heaptrack_gui heaptrack.myapp.12345.zst

3. Build for better profiling

bash
# Build with debug symbols (essential for readable backtraces)
cmake -S . -B build -DCMAKE_BUILD_TYPE=RelWithDebInfo
cmake --build build

# Then profile
heaptrack ./build/myapp

4. Interpreting heaptrack_print output

bash
heaptrack_print heaptrack.myapp.*.zst 2>/dev/null

Key sections:

text
total runtime: 2.34s
calls to allocation functions: 145,234 (62,064/s)
temporary allocations: 89,123 (38,087/s)
peak heap memory consumption: 45.23MB
peak RSS (including heap): 78.45MB
total memory leaked: 2.34MB

# Top allocation hotspots (by peak memory)
hotspot 1: 12.34MB peak
  myapp::cache::Cache::insert(...)
    at src/cache.cpp:142
  ...

# Top leaked allocations
leak 1: 2.34MB leaked in 1,234 allocations
  myapp::connection::Connection::new(...)
    at src/connection.cpp:67
MetricMeaning
total memory leakedMemory allocated but never freed
peak heap consumptionMaximum live heap at any point
temporary allocationsAllocated and freed within one call stack
calls to allocation functionsTotal malloc/new/realloc calls

5. Filtering and analysis options

bash
# Show top N hotspots
heaptrack_print -p 10 heaptrack.myapp.*.zst  # top 10 hotspots

# Show flamegraph data
heaptrack_print -f heaptrack.myapp.*.zst > alloc.folded
flamegraph.pl alloc.folded > alloc.svg

# Show only leaked allocations
heaptrack_print -l heaptrack.myapp.*.zst

# Show allocations above threshold
heaptrack_print --min-cost 1048576 heaptrack.myapp.*.zst  # >1MB only

# Short summary
heaptrack_print -s heaptrack.myapp.*.zst

6. Comparing two runs

bash
# Record baseline
heaptrack ./myapp --config baseline.conf
mv heaptrack.myapp.*.zst before.zst

# Make changes, record again
heaptrack ./myapp --config new.conf
mv heaptrack.myapp.*.zst after.zst

# Compare (shows diff of hotspots)
heaptrack_print before.zst | head -20 > before.txt
heaptrack_print after.zst  | head -20 > after.txt
diff before.txt after.txt

7. heaptrack vs Valgrind massif

FeatureheaptrackValgrind massif
Overhead~2-3x~20x
OutputCompressed trace + GUIText/ms_print
Leak detectionYesYes
Peak trackingYesYes
Temporal viewYes (GUI)Yes (ms_print)
PlatformLinux onlyLinux, macOS
Needs recompileNoNo
Call graphFull stack tracesFull stack traces

Use heaptrack for most cases; use massif when you need platform portability or detailed snapshot comparison.

8. Integration with Rust

heaptrack works with Rust binaries when using the system allocator:

rust
// Rust: use system allocator so heaptrack can intercept
use std::alloc::System;
#[global_allocator]
static A: System = System;
bash
# Profile Rust binary
cargo build --release
heaptrack ./target/release/myapp

# Note: debug symbols improve backtraces
cargo build --profile release-with-debug
heaptrack ./target/release-with-debug/myapp

For heaptrack_print output reference and GUI usage, see references/heaptrack-analysis.md.

Related skills

  • Use skills/profilers/valgrind for Memcheck (correctness) and massif (alternative heap profiler)
  • Use skills/profilers/linux-perf for CPU profiling alongside memory profiling
  • Use skills/rust/rust-profiling for Rust-specific allocation profiling approaches
  • Use skills/runtimes/sanitizers — ASan LeakSanitizer for leak detection without profiling overhead
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