source: benchmark/readyQ/locality.rs@ 751e2eb

use std::ptr;
use std::sync::Arc;
use std::sync::atomic::{AtomicU64, Ordering};
use std::time::Instant;
use std::thread::{self, ThreadId};

use tokio::runtime::Builder;
use tokio::sync;

use clap::{App, Arg};
use num_format::{Locale, ToFormattedString};
use rand::Rng;

#[path = "../bench.rs"]
mod bench;

// ==================================================
struct MyData {
        data: Vec<u64>,
        ttid: ThreadId,
        _id: usize,
}

impl MyData {
        fn new(id: usize, size: usize) -> MyData {
                MyData {
                        data: vec![0; size],
                        ttid: thread::current().id(),
                        _id: id,
                }
        }

        fn moved(&mut self, ttid: ThreadId) -> u64 {
                if self.ttid == ttid {
                        return 0;
                }
                self.ttid = ttid;
                return 1;
        }

        fn access(&mut self, idx: usize) {
                let l = self.data.len();
                self.data[idx % l] += 1;
        }
}

struct MyDataPtr {
        ptr: *mut MyData,
}

unsafe impl std::marker::Send for MyDataPtr{}

// ==================================================
struct MyCtx {
        s: sync::Semaphore,
        d: MyDataPtr,
        ttid: ThreadId,
        _id: usize,
}

impl MyCtx {
        fn new(d: *mut MyData, id: usize) -> MyCtx {
                MyCtx {
                        s: sync::Semaphore::new(0),
                        d: MyDataPtr{ ptr: d },
                        ttid: thread::current().id(),
                        _id: id
                }
        }

        fn moved(&mut self, ttid: ThreadId) -> u64 {
                if self.ttid == ttid {
                        return 0;
                }
                self.ttid = ttid;
                return 1;
        }
}
// ==================================================
// Atomic object where a single thread can wait
// May exchanges data
struct MySpot {
        ptr: AtomicU64,
        _id: usize,
}

impl MySpot {
        fn new(id: usize) -> MySpot {
                let r = MySpot{
                        ptr: AtomicU64::new(0),
                        _id: id,
                };
                r
        }

        fn one() -> u64 {
                1
        }

        // Main handshake of the code
        // Single seat, first thread arriving waits
        // Next threads unblocks current one and blocks in its place
        // if share == true, exchange data in the process
        async fn put( &self, ctx: &mut MyCtx, data: MyDataPtr, share: bool) -> (*mut MyData, bool) {
                {
                        // Attempt to CAS our context into the seat
                        let raw = {
                                loop {
                                        let expected = self.ptr.load(Ordering::Relaxed) as u64;
                                        if expected == MySpot::one() { // Seat is closed, return
                                                let r: *const MyData = ptr::null();
                                                return (r as *mut MyData, true);
                                        }
                                        let got = self.ptr.compare_and_swap(expected, ctx as *mut MyCtx as u64, Ordering::SeqCst);
                                        if got == expected {
                                                break expected;// We got the seat
                                        }
                                }
                        };

                        // If we aren't the fist in, wake someone
                        if raw != 0 {
                                let val: &mut MyCtx = unsafe{ &mut *(raw as *mut MyCtx) };
                                // If we are sharing, give them our data
                                if share {
                                        val.d.ptr = data.ptr;
                                }

                                // Wake them up
                                val.s.add_permits(1);
                        }
                }

                // Block once on the seat
                ctx.s.acquire().await.forget();

                // Someone woke us up, get the new data
                let ret = ctx.d.ptr;
                return (ret, false);
        }

        // Shutdown the spot
        // Wake current thread and mark seat as closed
        fn release(&self) {
                let val = self.ptr.swap(MySpot::one(), Ordering::SeqCst);
                if val == 0 {
                        return
                }

                // Someone was there, release them
                unsafe{ &mut *(val as *mut MyCtx) }.s.add_permits(1)
        }
}

// ==================================================
// Struct for result, Go doesn't support passing tuple in channels
struct Result {
        count: u64,
        gmigs: u64,
        dmigs: u64,
}

impl Result {
        fn new() -> Result {
                Result{ count: 0, gmigs: 0, dmigs: 0}
        }

        fn add(&mut self, o: Result) {
                self.count += o.count;
                self.gmigs += o.gmigs;
                self.dmigs += o.dmigs;
        }
}

// ==================================================
// Random number generator, Go's native one is to slow and global
fn __xorshift64( state: &mut u64 ) -> usize {
        let mut x = *state;
        x ^= x << 13;
        x ^= x >> 7;
        x ^= x << 17;
        *state = x;
        x as usize
}

// ==================================================
// Do some work by accessing 'cnt' cells in the array
fn work(data: &mut MyData, cnt: u64, state : &mut u64) {
        for _ in 0..cnt {
                data.access(__xorshift64(state))
        }
}

async fn local(start: Arc<sync::Barrier>, idata: MyDataPtr, spots : Arc<Vec<MySpot>>, cnt: u64, share: bool, id: usize, exp: Arc<bench::BenchData>) -> Result{
        let mut state = rand::thread_rng().gen::<u64>();
        let mut data = idata;
        let mut ctx = MyCtx::new(data.ptr, id);
        let _size = unsafe{ &mut *data.ptr }.data.len();

        // Prepare results
        let mut r = Result::new();

        // Wait for start
        start.wait().await;

        // Main loop
        loop {
                // Touch our current data, write to invalidate remote cache lines
                work(unsafe{ &mut *data.ptr }, cnt, &mut state);

                // Wait on a random spot
                let i = (__xorshift64(&mut state) as usize) % spots.len();
                let closed = {
                        let (d, c) = spots[i].put(&mut ctx, data, share).await;
                        data = MyDataPtr{ ptr: d };
                        c
                };

                // Check if the experiment is over
                if closed { break }                                                   // yes, spot was closed
                if  exp.clock_mode && exp.stop.load(Ordering::Relaxed) { break }  // yes, time's up
                if !exp.clock_mode && r.count >= exp.stop_count { break }         // yes, iterations reached

                assert_ne!(data.ptr as *const MyData, ptr::null());

                let d = unsafe{ &mut *data.ptr };

                // Check everything is consistent
                debug_assert_eq!(d.data.len(), _size);

                // write down progress and check migrations
                let ttid = thread::current().id();
                r.count += 1;
                r.gmigs += ctx .moved(ttid);
                r.dmigs += d.moved(ttid);
        }

        exp.threads_left.fetch_sub(1, Ordering::SeqCst);
        r
}


// ==================================================
fn main() {
        let options = App::new("Locality Tokio")
                .args(&bench::args())
                .arg(Arg::with_name("size")      .short("w").long("worksize")  .takes_value(true).default_value("2").help("Size of the array for each threads, in words (64bit)"))
                .arg(Arg::with_name("work")      .short("c").long("workcnt")   .takes_value(true).default_value("2").help("Number of words to touch when working (random pick, cells can be picked more than once)"))
                .arg(Arg::with_name("share")     .short("s").long("share")     .takes_value(true).default_value("true").help("Pass the work data to the next thread when blocking"))
                .get_matches();

        let nthreads   = options.value_of("nthreads").unwrap().parse::<usize>().unwrap();
        let nprocs     = options.value_of("nprocs").unwrap().parse::<usize>().unwrap();
        let wsize      = options.value_of("size").unwrap().parse::<usize>().unwrap();
        let wcnt       = options.value_of("work").unwrap().parse::<u64>().unwrap();
        let share      = options.value_of("share").unwrap().parse::<bool>().unwrap();

        // Check params
        if ! (nthreads > nprocs) {
                panic!("Must have more threads than procs");
        }

        let s = (1000000 as u64).to_formatted_string(&Locale::en);
        assert_eq!(&s, "1,000,000");

        let exp = Arc::new(bench::BenchData::new(options, nprocs));
        let mut results = Result::new();

        let mut elapsed : std::time::Duration = std::time::Duration::from_secs(0);

        let mut data_arrays : Vec<MyData> = (0..nthreads).map(|i| MyData::new(i, wsize)).rev().collect();
        let spots : Arc<Vec<MySpot>> = Arc::new((0..nthreads - nprocs).map(|i| MySpot::new(i)).rev().collect());
        let barr = Arc::new(sync::Barrier::new(nthreads + 1));

        let runtime = Builder::new_multi_thread()
                .worker_threads(nprocs)
                .enable_all()
                .build()
                .unwrap();

        runtime.block_on(async
                {
                        let thrds: Vec<_> = (0..nthreads).map(|i| {
                                debug_assert!(i < data_arrays.len());

                                runtime.spawn(local(
                                        barr.clone(),
                                        MyDataPtr{ ptr: &mut data_arrays[i] },
                                        spots.clone(),
                                        wcnt,
                                        share,
                                        i,
                                        exp.clone(),
                                ))
                        }).collect();


                        println!("Starting");

                        let start = Instant::now();
                        barr.wait().await;

                        elapsed = exp.wait(&start).await;

                        println!("\nDone");

                        // release all the blocked threads
                        for s in &* spots {
                                s.release();
                        }

                        println!("Threads released");

                        // Join and accumulate results
                        for t in thrds {
                                results.add( t.await.unwrap() );
                        }

                        println!("Threads joined");
                }
        );

        println!("Duration (ms)          : {}", (elapsed.as_millis()).to_formatted_string(&Locale::en));
        println!("Number of processors   : {}", (nprocs).to_formatted_string(&Locale::en));
        println!("Number of threads      : {}", (nthreads).to_formatted_string(&Locale::en));
        println!("Work size (64bit words): {}", (wsize).to_formatted_string(&Locale::en));
        println!("Total Operations(ops)  : {:>15}", (results.count).to_formatted_string(&Locale::en));
        println!("Total G Migrations     : {:>15}", (results.gmigs).to_formatted_string(&Locale::en));
        println!("Total D Migrations     : {:>15}", (results.dmigs).to_formatted_string(&Locale::en));
        println!("Ops per second         : {:>15}", (((results.count as f64) / elapsed.as_secs() as f64) as u64).to_formatted_string(&Locale::en));
        println!("ns per ops             : {:>15}", ((elapsed.as_nanos() as f64 / results.count as f64) as u64).to_formatted_string(&Locale::en));
        println!("Ops per threads        : {:>15}", (results.count / nthreads as u64).to_formatted_string(&Locale::en));
        println!("Ops per procs          : {:>15}", (results.count / nprocs as u64).to_formatted_string(&Locale::en));
        println!("Ops/sec/procs          : {:>15}", ((((results.count as f64) / nprocs as f64) / elapsed.as_secs() as f64) as u64).to_formatted_string(&Locale::en));
        println!("ns per ops/procs       : {:>15}", ((elapsed.as_nanos() as f64 / (results.count as f64 / nprocs as f64)) as u64).to_formatted_string(&Locale::en));
}