[release] cpufreq v1.0.0

A simple tool to show the current average CPU frequency across all
CPU cores. Can be given the argument `-a` to show frequency for each
individual core.

.gitignore

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+/target

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "cpufreq"
+version = "1.0.0"

Cargo.toml

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+[package]
+name = "cpufreq"
+version = "1.0.0"
+edition = "2021"
+
+[profile.release]
+lto = true
+debug = false
+strip = true
+panic = "unwind"
+codegen-units = 1

README.md

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+# cpufreq
+
+## About
+### Features
+A simple tool to show the current average CPU frequency across all
+CPU cores. Can be given the argument `-a` to show frequency for each
+individual core (cores sorted according to their number in the kernel).
+
+### Usage
+`cpufreq [-a]`
+
+### Design goal
+The goal was to create
+* a minimal Linux program with no dependencies
+* that runs on any `x86_64` system without the need for a specific C library version to be present
+* and is very fast (takes less than 1ms as of `v1.0`)
+
+## Platform support
+This program is linux only.
+There are _no_ plans to change that.

rustfmt.toml

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+group_imports = "StdExternalCrate"
+imports_granularity = "Crate"
+imports_layout = "HorizontalVertical"

src/main.rs

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+use std::{env::args, fs};
+
+static LINUX_SYSFS_CPUFREQ_BASE_DIR: &str = "/sys/devices/system/cpu/cpufreq";
+
+fn show_all() {
+    let mut cpu_num = 0;
+
+    loop {
+        let path = format!("{LINUX_SYSFS_CPUFREQ_BASE_DIR}/policy{cpu_num}/scaling_cur_freq");
+
+        if let Ok(scaling_cur_freq) = fs::read_to_string(path) {
+            println!("{}", scaling_cur_freq.trim().parse::<u64>().unwrap() / 1000);
+        } else {
+            break;
+        }
+
+        cpu_num += 1;
+    }
+}
+
+fn show_average() {
+    let mut sum = 0;
+    let mut count = 0;
+
+    for dir in fs::read_dir(LINUX_SYSFS_CPUFREQ_BASE_DIR).unwrap() {
+        let mut path = dir.unwrap().path();
+        path.push("scaling_cur_freq");
+
+        if let Ok(scaling_cur_freq) = fs::read_to_string(path) {
+            let freq: u64 = scaling_cur_freq.trim().parse().unwrap();
+            sum += freq;
+            count += 1;
+        }
+    }
+
+    println!("{}", sum / count / 1000);
+}
+
+fn main() {
+    let all = args()
+        .nth(1)
+        .filter(|opt| opt == "-a" || opt == "--all")
+        .is_some();
+
+    match all {
+        true => show_all(),
+        false => show_average(),
+    }
+}