STRUCT PERF_FILE_HEADER(9)

💖 struct perf_file_header(9) 💖

ok so bestie, welcome to the struct perf_file_header(9) page from the Kernel API Manual — this is the little on-disk glow-up that heads up a perf file, and honestly? it's giving ✨*manifest*✨ energy. let's get into it 🎀

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🌸 NAME 🌸

struct perf_file_header — the header representation on disk, no cap. this is literally the first thing that shows up when your perf file wakes up and chooses main character energy 💅

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✨ SYNOPSIS ✨

struct perf_file_header {
    u64 magic;
    u64 size;
    u64 attr_size;
    struct perf_file_section        attrs;
    struct perf_file_section        data;
    struct perf_file_section        event_types;
    unsigned long adds_features[BITS_TO_LONGS( HEADER_FEAT_BITS)];
};

like, look at her. seven whole fields. iconic. 👑

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🦋 Members 🦋

okay so let's go field by field because every single one matters, fr fr 🫶

• magic — holds "PERFILE2". that's the vibe check at the door — if this doesn't match, the file is not getting in 🔥
• size — the size of this header, literally sizeof(struct perf_file_header). she knows her own measurements 💖
• attr_size — the size of the attrs entries, and that's sizeof(struct perf_event_attr) + sizeof(struct perf_file_section). yes, both. do the math, don't skip a term 🧮✨
• attrs — the offset and size of the file section holding the attributes. that's where the attr crew lives 🎀
• data — the offset and size of the file section holding regular event data. the actual main event data, literally 🌈
• event_types — ignored. yeah. she's just there. not me pointing at her 💀 (the manpage said ignored, so bestie, we ignore her 🙈)
• adds_features — a bitmap of features. important detail: the features are immediately after the data section. don't go hunting elsewhere, they're right there 🕵️‍♀️⭐

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👑 SEE ALSO 👑

• Kernel file ./tools/perf/util/header.h — go read the source, iykyk 📖💜

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and that's the whole page, bestie!! 🎉 no notes. now go forth and parse some headers, you absolute icon 🌟

with love from the Kernel API Manual, struct perf_file_header(9), brought to you by ./tools/perf/util 🫶 — dropped October 2026, mark your calendars 🎀✨