forked from beerpsi/chuniio-yubideck
79 lines
2.0 KiB
Rust
79 lines
2.0 KiB
Rust
use std::thread;
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use clap::Parser;
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use shared_memory::*;
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/// Spawns N threads that increment a value to 100
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#[derive(Parser)]
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#[clap(author, version, about)]
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struct Args {
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/// Number of threads to spawn
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num_threads: usize,
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/// Count to this value
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#[clap(long, short, default_value_t = 50)]
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count_to: u8,
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}
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fn main() {
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env_logger::init();
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let args = Args::parse();
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if args.num_threads < 1 {
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eprintln!("Invalid number of threads");
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return;
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}
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let mut threads = Vec::with_capacity(args.num_threads);
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let _ = std::fs::remove_file("basic_mapping");
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let max = args.count_to;
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// Spawn N threads
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for i in 0..args.num_threads {
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let thread_id = i + 1;
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threads.push(thread::spawn(move || {
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increment_value("basic_mapping", thread_id, max);
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}));
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}
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// Wait for threads to exit
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for t in threads.drain(..) {
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t.join().unwrap();
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}
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}
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/// Increments a value that lives in shared memory
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fn increment_value(shmem_flink: &str, thread_num: usize, max: u8) {
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// Create or open the shared memory mapping
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let shmem = match ShmemConf::new().size(4096).flink(shmem_flink).create() {
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Ok(m) => m,
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Err(ShmemError::LinkExists) => ShmemConf::new().flink(shmem_flink).open().unwrap(),
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Err(e) => {
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eprintln!(
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"Unable to create or open shmem flink {} : {}",
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shmem_flink, e
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);
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return;
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}
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};
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// Get pointer to the shared memory
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let raw_ptr = shmem.as_ptr();
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// WARNING: This is prone to race conditions as no sync/locking is used
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unsafe {
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while std::ptr::read_volatile(raw_ptr) < max {
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// Increment shared value by one
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*raw_ptr += 1;
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println!(
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"[thread:{}] {}",
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thread_num,
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std::ptr::read_volatile(raw_ptr)
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);
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// Sleep for a bit
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std::thread::sleep(std::time::Duration::from_secs(1));
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}
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}
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}
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