STRUCT UNCORE_DATA(9)

💅 struct uncore_data(9) — the kernel API glow-up 🦋

okay so first things first, bestie: this whole page is from Kernel API Manual, and the star of the show is struct uncore_data — literally "Encapsulate all uncore data." that's the NAME, that's the whole vibe. one struct, all the uncore lore, no cap 💖

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✨ SYNOPSIS ✨

like, here's the whole thing laid out, and yes you're gonna read every field because we do not skip around here 🎀

struct uncore_data {
    u64 stored_uncore_data;
    u32 initial_min_freq_khz;
    u32 initial_max_freq_khz;
    int control_cpu;
    bool valid;
    int package_id;
    int die_id;
    int domain_id;
    int cluster_id;
    int seqnum_id;
    int instance_id;
    char name[32];
    u16 agent_type_mask;
    struct attribute_group uncore_attr_group;
    struct kobj_attribute max_freq_khz_kobj_attr;
    struct kobj_attribute min_freq_khz_kobj_attr;
    struct kobj_attribute initial_max_freq_khz_kobj_attr;
    struct kobj_attribute initial_min_freq_khz_kobj_attr;
    struct kobj_attribute current_freq_khz_kobj_attr;
    struct kobj_attribute domain_id_kobj_attr;
    struct kobj_attribute fabric_cluster_id_kobj_attr;
    struct kobj_attribute package_id_kobj_attr;
    struct kobj_attribute elc_low_threshold_percent_kobj_attr;
    struct kobj_attribute elc_high_threshold_percent_kobj_attr;
    struct kobj_attribute elc_high_threshold_enable_kobj_attr;
    struct kobj_attribute elc_floor_freq_khz_kobj_attr;
    struct kobj_attribute agent_types_kobj_attr;
    struct kobj_attribute die_id_kobj_attr;
    struct kobj_attribute instance_id_kobj_attr;
    struct attribute *uncore_attrs[16];
};

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🌸 Members 🌸

okay so now we go member by member, like a tour of the group chat 💅

• stored_uncore_data — the last user-changed MSR 620 value 🫶. it's kept around so it can be restored on system resume. so it's giving "save point" energy, honestly iconic.
• initial_min_freq_khz — the sampled minimum uncore frequency at driver init ⭐
• initial_max_freq_khz — the sampled maximum uncore frequency at driver init ⭐
• control_cpu — the designated CPU for a die to read/write 👑
• valid — marks the data valid/invalid, the little vibe check flag 💀
• package_id — the package id for this instance
• die_id — the die id for this instance
• domain_id — the power domain id for this instance
• cluster_id — the cluster id in a domain
• seqnum_id — a unique sequential id that gets appended to the directory name
• instance_id — die indices or feature instances for a single TPMI device
• name — the sysfs entry name for this instance
• agent_type_mask — a bit mask of all hardware agents for this domain 🔥
• uncore_attr_group — attribute group storage
• max_freq_khz_kobj_attr — storage for the kobject attribute max_freq_khz
• min_freq_khz_kobj_attr — storage for the kobject attribute min_freq_khz
• initial_max_freq_khz_kobj_attr — storage for the kobject attribute initial_max_freq_khz
• initial_min_freq_khz_kobj_attr — storage for the kobject attribute initial_min_freq_khz
• current_freq_khz_kobj_attr — storage for the kobject attribute current_freq_khz
• domain_id_kobj_attr — storage for the kobject attribute domain_id
• fabric_cluster_id_kobj_attr — storage for the kobject attribute fabric_cluster_id
• package_id_kobj_attr — storage for the kobject attribute package_id
• elc_low_threshold_percent_kobj_attr — storage for the kobject attribute elc_low_threshold_percent
• elc_high_threshold_percent_kobj_attr — storage for the kobject attribute elc_high_threshold_percent
• elc_high_threshold_enable_kobj_attr — storage for the kobject attribute elc_high_threshold_enable
• elc_floor_freq_khz_kobj_attr — storage for the kobject attribute elc_floor_freq_khz
• agent_types_kobj_attr — storage for the kobject attribute agent_type
• die_id_kobj_attr — attribute storage for die_id information
• instance_id_kobj_attr — attribute storage for the instance_id value
• uncore_attrs — attribute storage for group creation

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🦋 Description 🦋

literally what it says on the tin, bestie: this structure is used to encapsulate all data related to uncore sysfs settings for a die/package. every single sysfs setting, one struct, main character energy 👑

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.h — go read it, iykyk 🧚

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lowkey the whole page is one struct and its members, but don't let that fool you — it's holding a lot of uncore secrets 💜

okay that's the page!! and for the sign-off: this is from Kernel API Manual, dated October 2026, and the footer source got cut off at ./drivers/platform/x86/intel/u... — so shoutout to that truncated path, we love a mysterious ellipsis 🍓✨ slay, bye! 💅🫶