STRUCT AUXTRACE(9)

🦋 struct auxtrace(9) 🦋

okay bestie, welcome to the Kernel API Manual ✨ — this is the page for struct auxtrace, and honestly? it's giving backstage-pass energy. no cap.

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✨ NAME ✨

struct auxtrace — session callbacks that let AUX area data get decoded 💅

like, they're the little hook functions the decoder calls so it can actually make sense of your AUX data. iconic behavior tbh.

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🌸 SYNOPSIS 🌸

here's the whole struct, character for character, no edits from me (i would never):

struct auxtrace {
    int (*process_event)(struct perf_session *session, union perf_event *event, struct perf_sample *sample, const struct perf_tool *tool);
    int (*process_auxtrace_event)(struct perf_session *session, union perf_event *event, const struct perf_tool *tool);
    int (*queue_data)(struct perf_session *session, struct perf_sample *sample, union perf_event *event, u64 data_offset);
    void (*dump_auxtrace_sample)(struct perf_session *session, struct perf_sample *sample);
    int (*flush_events)(struct perf_session *session, const struct perf_tool *tool);
    void (*free_events)(struct perf_session *session);
    void (*free)(struct perf_session *session);
    bool (*evsel_is_auxtrace)(struct perf_session *session, struct evsel *evsel);
};

💖 Members 💖

• process_event — lets the decoder see all the session events 👀 every single one. it's nosy but make it useful.
• process_auxtrace_event — handles a PERF_RECORD_AUXTRACE event. that's literally its whole job and it ate.
• queue_data — queues an AUX sample or a PERF_RECORD_AUXTRACE event so it can be processed later 🎀 (yes, there's a u64 data_offset in there, keep it).
• dump_auxtrace_sample — dumps out the AUX area sample data. dump it, queen 💅
• flush_events — processes whatever data is still hanging around at the end. cleanup era ✨
• free_events — frees the resources tied to event processing. bye bestie 🫶
• free — frees the resources tied to the session itself. also bye 🫶

real talk: the struct also declares evsel_is_auxtrace (it returns a bool, takes a struct perf_session *session and a struct evsel *evsel) — but the Members list doesn't describe it, so i'm not gonna make up a description, that's not the vibe 🙈

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🌈 SEE ALSO 🌈

kernel file ./tools/perf/util/auxtrace.h, plus this whole little friend group right here:

• struct itrace_synth_opts(9)
• struct auxtrace_index_entry(9)
• struct auxtrace_index(9)
• struct auxtrace_buffer(9)
• struct auxtrace_queue(9)
• struct auxtrace_queues(9)
• struct auxtrace_heap_item(9)
• struct auxtrace_heap(9)
• struct auxtrace_mmap(9)
• struct auxtrace_mmap_params(9)
• struct auxtrace_record(9)
• struct addr_filter(9)
• struct addr_filters(9)

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and that's the whole page, bestie 🎀 it lives at ./tools/perf/util, dated October 2026, and yes it's still called struct auxtrace(9) — go decode some AUX data, you've got this 💜🔥