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83 lines
2.5 KiB
Rust
83 lines
2.5 KiB
Rust
use crate::setup::{Input, Knobs, ParDatabase, ParDatabaseImpl, WithValue};
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use salsa::{Database, ParallelDatabase};
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/// Test where two threads are executing sum. We show that they can
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/// both be executing sum in parallel by having thread1 wait for
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/// thread2 to send a signal before it leaves (similarly, thread2
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/// waits for thread1 to send a signal before it enters).
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#[test]
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fn true_parallel_different_keys() {
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let db = ParDatabaseImpl::default();
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db.query(Input).set('a', 100);
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db.query(Input).set('b', 010);
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db.query(Input).set('c', 001);
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// Thread 1 will signal stage 1 when it enters and wait for stage 2.
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let thread1 = std::thread::spawn({
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let db = db.fork();
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move || {
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let v = db.knobs().sum_signal_on_entry.with_value(1, || {
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db.knobs()
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.sum_wait_for_on_exit
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.with_value(2, || db.sum("a"))
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});
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v
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}
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});
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// Thread 2 will wait_for stage 1 when it enters and signal stage 2
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// when it leaves.
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let thread2 = std::thread::spawn({
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let db = db.fork();
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move || {
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let v = db.knobs().sum_wait_for_on_entry.with_value(1, || {
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db.knobs().sum_signal_on_exit.with_value(2, || db.sum("b"))
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});
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v
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}
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});
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assert_eq!(thread1.join().unwrap(), 100);
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assert_eq!(thread2.join().unwrap(), 010);
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}
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/// Add a test that tries to trigger a conflict, where we fetch
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/// `sum("abc")` from two threads simultaneously, and of them
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/// therefore has to block.
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#[test]
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fn true_parallel_same_keys() {
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let db = ParDatabaseImpl::default();
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db.query(Input).set('a', 100);
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db.query(Input).set('b', 010);
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db.query(Input).set('c', 001);
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// Thread 1 will wait_for a barrier in the start of `sum`
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let thread1 = std::thread::spawn({
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let db = db.fork();
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move || {
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let v = db.knobs().sum_signal_on_entry.with_value(1, || {
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db.knobs()
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.sum_wait_for_on_entry
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.with_value(2, || db.sum("abc"))
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});
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v
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}
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});
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// Thread 2 will sync barrier *just* before calling `sum`. Doesn't
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// guarantee the race we want but makes it highly likely.
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let thread2 = std::thread::spawn({
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let db = db.fork();
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move || {
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db.knobs().signal.wait_for(1);
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db.knobs().signal.signal(2);
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db.sum("abc")
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}
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});
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assert_eq!(thread1.join().unwrap(), 111);
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assert_eq!(thread2.join().unwrap(), 111);
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}
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