STRUCT MSM_PERFCNTR_CONTEXT_STATE(9)

💜 struct msm_perfcntr_context_state(9) 💜

ok okay so this is a Kernel API Manual page, section 9, all about struct msm_perfcntr_context_state — the per-msm_context counter state. yes bestie, we're going deep into the DRM/msm mines today, grab a lil snack 🍓

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✨ NAME ✨

struct msm_perfcntr_context_state — literally the per-msm_context counter state, that's the whole vibe 💅

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🎀 SYNOPSIS 🎀

struct msm_perfcntr_context_state {
    unsigned dummy;
    unsigned reserved_counters[];
};

look at her. small. mighty. flexible array at the end. iconic behavior ngl 👑

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🌸 Members 🌸

the little guys inside

• dummy — a whole unsigned just existing as structural support, because some compilers simply cannot handle a struct that's only a flex array 😭 like they throw a fit. so dummy is here to keep the peace. main character energy honestly 🫶
• reserved_counters — the number of reserved counters, indexed by perfcntr group. that's the index, that's the data, no cap 📊

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🦋 Description 🦋

ok so listen, a given counter can be in one of three states, and this is the whole plot:

1. it can be completely unused — just chilling, not doing anything 🌈
2. it can be reserved for global counter collection exclusively — like, only for that, don't even try it
3. it can be reserved for local per-context counter collection inclusively — the inclusive bestie version 💖

and here's the slay: multiple contexts can reserve the same counter at the same time. not a bug. not a fight. because SEL reg programming and counter begin/end sampling happen locally — meaning within a single GEM_SUBMIT ioctl 🔥 so everyone's doing their own thing in their own little sandbox and nobody's stepping on anybody. periodt.

ngl this is the kind of design decision that makes you go "ohhhh" out loud 🙈

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⭐ SEE ALSO ⭐

• Kernel file ./drivers/gpu/drm/msm/msm_perfcntr.h — go read it, it's right there, it's giving source-of-truth 🧚
• struct msm_perfcntr_stream(9) — the sibling, the companion, the other one you also need 💀

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and that's the whole page bestie!! 💅✨ this one lives in ./drivers/gpu/drm/msm and it's dated October 2026, so like... future vibes fr fr 🕰️💜 love that for us. now go read msm_perfcntr_stream(9) too, i'm not asking 🎀