STRUCT ISST_PERF_LEVEL_INFO(9)

💜 struct isst_perf_level_info — the kernel API manual, but make it make sense

okay so bestie, this is the man page for struct isst_perf_level_info, and it lives in the Kernel API Manual (yes, the kernel has lore too). I'm gonna walk you through it like we're on facetime, but every single field is staying exactly where it is — no cap 💅

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🦋 NAME

struct isst_perf_level_info — the struct you use to get the deets on your SST-PP levels, periodt ✨

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🌸 SYNOPSIS

here's the whole thing, character for character, don't touch it:

struct isst_perf_level_info {
    __u8 socket_id;
    __u8 power_domain_id;
    __u8 max_level;
    __u8 feature_rev;
    __u8 level_mask;
    __u8 current_level;
    __u8 feature_state;
    __u8 locked;
    __u8 enabled;
    __u8 sst_tf_support;
    __u8 sst_bf_support;
 };

like… eleven little __u8 besties all lined up. iconic. 🌈

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🎀 Members

okay this is the part where we do a vibe check on every single field, one by one, no skipping 🫶

• socket_id — the socket/package id. which socket are we even talking about, iykyk.
• power_domain_id — the Power Domain id. that's the domain, but make it power. ⚡
• max_level — the maximum performance level the platform supports. the ceiling, the limit, the final boss.
• feature_rev — the feature revision for SST-PP supported by the platform. which version of the feature we're dealing with.
• level_mask — a mask of the supported performance levels. mask on, mask off, this one tracks which levels exist at all 💀
• current_level — the current performance level. where we're at right now, literally.
• feature_state — the SST-BF and SST-TF (enabled/disabled) status at the current level. two features, one field, the way that it's efficient 🧚
• locked — whether the SST-PP performance level change is locked/unlocked. locked = don't touch it, bestie 🔒
• enabled — whether the SST-PP feature is enabled or not. simple. clean. we respect that.
• sst_tf_support — the SST-TF support status at this level.
• sst_bf_support — the SST-BF support status at this level. (yes, TF and BF are two different letters, don't merge them, I will know 🙈)

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✨ Description

so basically, this struct is how you get the SST-PP details — and you do it using the IOCTL ISST_IF_PERF_LEVELS. that's the whole plot. that's the movie. 🍓

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👑 SEE ALSO

okay here comes the family tree, and I am NOT cutting anyone off:

Kernel file ./include/uapi/linux/isst_if.h, plus these sibling structs:

• struct isst_if_platform_info(9)
• struct isst_if_cpu_map(9)
• struct isst_if_cpu_maps(9)
• struct isst_if_io_reg(9)
• struct isst_if_io_regs(9)
• struct isst_if_mbox_cmd(9)
• struct isst_if_mbox_cmds(9)
• struct isst_if_msr_cmd(9)
• struct isst_if_msr_cmds(9)
• struct isst_core_power(9)
• struct isst_clos_param(9)
• struct isst_if_clos_assoc(9)
• struct isst_if_clos_assoc_cmds(9)
• struct isst_tpmi_instance_count(9)
• struct isst_perf_level_control(9)
• struct isst_perf_feature_control(9)
• struct isst_perf_level_data_info(9)
• struct isst_perf_level_fabric_info(9)
• struct isst_perf_level_cpu_mask(9)
• struct isst_base_freq_info(9)
• struct isst_turbo_freq_info(9)

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fr fr, that's the whole page. go read the header file if you want the full cinematic universe 💖

and that's the wrap, bestie — brought to you from the source file path ./include/uapi/linux, dated October 2026, straight out of the Kernel API Manual. slay, bye 👋💅✨