EST(4)

💖 EST 💖 — bestie edition

okay so this is the manual page for est, aka Enhanced Speedstep Technology, from the Kernel Interfaces Manual. it's a whole vibe, it's giving "your CPU but make it choose its own energy level" ✨

---

🌸 NAME 🌸

est — Enhanced Speedstep Technology 🦋

---

✨ SYNOPSIS ✨

so like, if you want this capability living inside your kernel, you drop this line into your kernel configuration file:

device cpufreq

that's it. that's the whole thing. 💅

---

💜 DESCRIPTION 💜

the est interface is what gives you support for the Intel Enhanced Speedstep Technology. iconic behavior fr fr.

lowkey important though: est capabilities are automatically loaded by the cpufreq(4) driver. you don't gotta do anything. it just shows up. main character energy 🎀

---

🎀 LOADER TUNABLES 🎀

the whole point of the est interface is to let cpufreq(4) access and implement Intel Enhanced SpeedStep Technology via acpi(4) and the acpi_perf interface accessors. iykyk.

and listen — if the default settings are not optimal for you, these following sysctls can be used to modify or monitor est behavior. obsessed with options tbh.

• hw.est.msr_info — attempts to infer information from direct probing of the msr. bestie, this should only be used in diagnostic cases. like, only only. (default 0)
• hw.est.strict — validates that the frequency requested is accepted by the CPU when set. it appears that this will only work on single core cpus. so yeah. (default 0)

---

💅 SYSCTL VARIABLES 💅

the following sysctl(8) values are available. get into it:

• dev.est.%d.%desc — description of support, almost always Enhanced SpeedStep Frequency Control.

dev.est.0.%desc: Enhanced SpeedStep Frequency Control

• dev.est.%d.%driver — driver in use, always est.

dev.est.0.%driver: est

• dev.est.%d.%parent — the CPU that is exposing these frequencies. for example cpu0.

dev.est.0.%parent: cpu0

• dev.est.%d.freq_settings. — the valid frequencies that are allowed by this CPU and their step values. this is the good stuff 🔥

dev.est.0.freq_settings: 2201/45000 2200/45000 2000/39581 1900/37387
        1800/34806 1700/32703 1600/30227 1500/28212 1400/25828
        1300/23900 1200/21613 1100/19775 1000/17582 900/15437 800/13723

---

😭 DIAGNOSTICS 😭

est%d: <Enhanced SpeedStep Frequency Control> on cpu%d

indicates normal startup of this interface. slay, everything's fine, we love a healthy attach 🫶

---

est: CPU supports Enhanced Speedstep, but is not recognized.
est: cpu_vendor GenuineIntel, msr 471c471c0600471c
device_attach: est%d attach returned 6

okay so this one means all attempts to attach to this interface have failed. 💀

this usually indicates an improper BIOS setting restricting O/S control of the CPU speeds. consult your BIOS documentation for more details. no cap, go read the BIOS docs.

---

🌈 COMPATIBILITY 🌈

est is only found on supported Intel CPUs. if you're not on one of those... yeah. not for you bestie 🙈

---

⭐ SEE ALSO ⭐

• cpufreq(4)
• Intel 64 and IA-32 Architectures Software Developer Manuals, http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html.

---

👑 AUTHORS 👑

this manual page was written by Sean Bruno <sbruno@FreeBSD.org>. thank you for your service king 🫡💖

---

and that's the whole page!! this one came from Debian, dated April 21, 2020, and it's the EST(4) page — go forth and let your CPU pick its own frequency, periodt 💅✨🦋