rust/crates/salsa/tests/parallel/parallel_cycle_one_recovers.rs
2024-03-05 12:16:19 +01:00

95 lines
2.4 KiB
Rust

//! Test for cycle recover spread across two threads.
//! See `../cycles.rs` for a complete listing of cycle tests,
//! both intra and cross thread.
use crate::setup::{Knobs, ParDatabaseImpl};
use salsa::ParallelDatabase;
// Recover cycle test:
//
// The pattern is as follows.
//
// Thread A Thread B
// -------- --------
// a1 b1
// | wait for stage 1 (blocks)
// signal stage 1 |
// wait for stage 2 (blocks) (unblocked)
// | signal stage 2
// (unblocked) wait for stage 3 (blocks)
// a2 |
// b1 (blocks -> stage 3) |
// | (unblocked)
// | b2
// | a1 (cycle detected)
// a2 recovery fn executes |
// a1 completes normally |
// b2 completes, recovers
// b1 completes, recovers
#[test]
fn parallel_cycle_one_recovers() {
let db = ParDatabaseImpl::default();
db.knobs().signal_on_will_block.set(3);
let thread_a = std::thread::spawn({
let db = db.snapshot();
move || db.a1(1)
});
let thread_b = std::thread::spawn({
let db = db.snapshot();
move || db.b1(1)
});
// We expect that the recovery function yields
// `1 * 20 + 2`, which is returned (and forwarded)
// to b1, and from there to a2 and a1.
assert_eq!(thread_a.join().unwrap(), 22);
assert_eq!(thread_b.join().unwrap(), 22);
}
#[salsa::query_group(ParallelCycleOneRecovers)]
pub(crate) trait TestDatabase: Knobs {
fn a1(&self, key: i32) -> i32;
#[salsa::cycle(recover)]
fn a2(&self, key: i32) -> i32;
fn b1(&self, key: i32) -> i32;
fn b2(&self, key: i32) -> i32;
}
fn recover(_db: &dyn TestDatabase, _cycle: &salsa::Cycle, key: &i32) -> i32 {
tracing::debug!("recover");
key * 20 + 2
}
fn a1(db: &dyn TestDatabase, key: i32) -> i32 {
// Wait to create the cycle until both threads have entered
db.signal(1);
db.wait_for(2);
db.a2(key)
}
fn a2(db: &dyn TestDatabase, key: i32) -> i32 {
db.b1(key)
}
fn b1(db: &dyn TestDatabase, key: i32) -> i32 {
// Wait to create the cycle until both threads have entered
db.wait_for(1);
db.signal(2);
// Wait for thread A to block on this thread
db.wait_for(3);
db.b2(key)
}
fn b2(db: &dyn TestDatabase, key: i32) -> i32 {
db.a1(key)
}