STRUCT CALL_RETURN(9)

🎀 struct call_return(9) 🎀

okay bestie, welcome to the struct call_return page — it's from the Kernel API Manual and it's literally all about paired call/return information. think of it as the receipts for a function call and its return, matched up like two halves of a friendship bracelet. 🫶

✨ SYNOPSIS ✨

struct call_return {
    struct thread *thread;
    struct comm *comm;
    struct call_path *cp;
    u64 call_time;
    u64 return_time;
    u64 branch_count;
    u64 insn_count;
    u64 cyc_count;
    u64 call_ref;
    u64 return_ref;
    u64 db_id;
    u64 parent_db_id;
    u32 flags;
 };

that's the whole struct, no cap. every field is iconic in its own way, and we're about to go through them one by one 💅

🌸 Members 🌸

• thread — the thread in which the call/return occurred. the main character, basically 🧚
• comm — the comm in which the call/return occurred. yes, its own field, don't ask, it's giving thorough.
• cp — the call path. the whole scenic route of how we got here 🦋
• call_time — timestamp of the call (if known). note the if known — sometimes we just don't know, and that's okay 😭
• return_time — timestamp of the return (if known). same vibe check as above ✨
• branch_count — number of branches seen between the call and the return. counting the plot twists 🔥
• insn_count — approx. number of instructions between the call and the return. key word approx., we're not doing exact math here ngl
• cyc_count — approx. number of cycles between the call and the return. also approximate, also slaying ⭐
• call_ref — external reference to the 'call' sample (e.g. db_id). it's a pointer to the call's other identity, iykyk
• return_ref — external reference to the 'return' sample (e.g. db_id). same but for the return half 💖
• db_id — id used for db-export. that's it, that's the field 👑
• parent_db_id — id of the parent call, used for db-export. the parent call is so main character energy 🌈
• flags — the Call/Return flags. unspecified flags, unspecified vibes, we love a mysterious icon 💀

🦋 SEE ALSO 🦋

• Kernel file ./tools/perf/util/thread-stack.h struct
• call_return_processor(9)

go read those too bestie, fr fr — this struct does not exist in a vacuum 💜

and that's the page!! a little sign-off from the source files: this masterpiece lives under ./tools/perf/util, dated October 2026, and it's filed as struct call_return(9). mwah, periodt 🍓✨