rayon example for wasting cpu time :)
Cargo Check, Format, Fix and Test / cargo CI (push) Successful in 1m31s
Details
Cargo Check, Format, Fix and Test / cargo CI (push) Successful in 1m31s
Details
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@ -1,43 +1,35 @@
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use std::sync::atomic::{AtomicU32, Ordering};
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use std::io::{prelude::*, Sink};
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use rayon::prelude::*;
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use tokio::{
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self,
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time::{interval, Interval},
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};
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static THE_NUMBER: AtomicU32 = AtomicU32::new(0);
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#[inline]
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fn incr() {
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// just add it
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THE_NUMBER.store(THE_NUMBER.load(Ordering::Relaxed) + 1, Ordering::Relaxed)
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}
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#[inline]
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fn get() -> u32 {
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THE_NUMBER.load(Ordering::Relaxed)
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}
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#[inline]
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async fn more() {
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rayon::spawn(|| incr())
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}
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// if we make these larger, our computer can be used as a heater🔥
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type Danum = u16;
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const CAP: usize = 1 << 14;
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#[tokio::main]
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async fn main() {
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// Lets say that we want to add numbers FAST
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println!("The number: {THE_NUMBER:?}");
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incr();
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assert_eq!(get(), 1);
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println!("The number: {THE_NUMBER:?}");
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println!("starting the threads");
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let mut interval = interval(tokio::time::Duration::from_millis(100));
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loop {
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tokio::select! {
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_ = interval.tick() => {
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println!("The number: {THE_NUMBER:?}");
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}
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_ = more() => ()
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};
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// Lets say that we want to add many numbers FAST
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let mut range: Vec<Danum> = Vec::with_capacity(CAP);
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// Initialize the values, probably zero
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unsafe {
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range.set_len(range.capacity());
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}
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let now = std::time::Instant::now();
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range.par_iter_mut().for_each(|num| {
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let mut sink = Sink::default();
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while *num < Danum::MAX {
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*num += 1; // cannot use `+=` on type `&u8`
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let _ = write!(sink, "{num}"); // just to disable the compiler from calculating it all
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// beforehand
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}
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});
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let sum: u128 = { range.par_iter().map(|n| *n as u128).sum::<u128>() };
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let eq = sum == CAP as u128 * Danum::MAX as u128;
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println!(
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"log cap: {}\nit worked: {eq}\nsum: {sum}\nlog_2(sum): {}\ntook: {:?}\nused threads: {}",
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CAP.ilog2(),
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sum.ilog2(),
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now.elapsed(),
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rayon::current_num_threads()
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);
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}
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