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|
use rand::seq::SliceRandom;
use rand::Rng;
use salsa::ParallelDatabase;
use salsa::Snapshot;
use salsa::{Cancelled, Database};
// Number of operations a reader performs
const N_MUTATOR_OPS: usize = 100;
const N_READER_OPS: usize = 100;
#[salsa::query_group(Stress)]
trait StressDatabase: salsa::Database {
#[salsa::input]
fn a(&self, key: usize) -> usize;
fn b(&self, key: usize) -> usize;
fn c(&self, key: usize) -> usize;
}
fn b(db: &dyn StressDatabase, key: usize) -> usize {
db.unwind_if_cancelled();
db.a(key)
}
fn c(db: &dyn StressDatabase, key: usize) -> usize {
db.b(key)
}
#[salsa::database(Stress)]
#[derive(Default)]
struct StressDatabaseImpl {
storage: salsa::Storage<Self>,
}
impl salsa::Database for StressDatabaseImpl {}
impl salsa::ParallelDatabase for StressDatabaseImpl {
fn snapshot(&self) -> Snapshot<StressDatabaseImpl> {
Snapshot::new(StressDatabaseImpl {
storage: self.storage.snapshot(),
})
}
}
#[derive(Clone, Copy, Debug)]
enum Query {
A,
B,
C,
}
enum MutatorOp {
WriteOp(WriteOp),
LaunchReader {
ops: Vec<ReadOp>,
check_cancellation: bool,
},
}
#[derive(Debug)]
enum WriteOp {
SetA(usize, usize),
}
#[derive(Debug)]
enum ReadOp {
Get(Query, usize),
}
impl rand::distributions::Distribution<Query> for rand::distributions::Standard {
fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Query {
*[Query::A, Query::B, Query::C].choose(rng).unwrap()
}
}
impl rand::distributions::Distribution<MutatorOp> for rand::distributions::Standard {
fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> MutatorOp {
if rng.gen_bool(0.5) {
MutatorOp::WriteOp(rng.gen())
} else {
MutatorOp::LaunchReader {
ops: (0..N_READER_OPS).map(|_| rng.gen()).collect(),
check_cancellation: rng.gen(),
}
}
}
}
impl rand::distributions::Distribution<WriteOp> for rand::distributions::Standard {
fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> WriteOp {
let key = rng.gen::<usize>() % 10;
let value = rng.gen::<usize>() % 10;
WriteOp::SetA(key, value)
}
}
impl rand::distributions::Distribution<ReadOp> for rand::distributions::Standard {
fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> ReadOp {
let query = rng.gen::<Query>();
let key = rng.gen::<usize>() % 10;
ReadOp::Get(query, key)
}
}
fn db_reader_thread(db: &StressDatabaseImpl, ops: Vec<ReadOp>, check_cancellation: bool) {
for op in ops {
if check_cancellation {
db.unwind_if_cancelled();
}
op.execute(db);
}
}
impl WriteOp {
fn execute(self, db: &mut StressDatabaseImpl) {
match self {
WriteOp::SetA(key, value) => {
db.set_a(key, value);
}
}
}
}
impl ReadOp {
fn execute(self, db: &StressDatabaseImpl) {
match self {
ReadOp::Get(query, key) => match query {
Query::A => {
db.a(key);
}
Query::B => {
let _ = db.b(key);
}
Query::C => {
let _ = db.c(key);
}
},
}
}
}
#[test]
fn stress_test() {
let mut db = StressDatabaseImpl::default();
for i in 0..10 {
db.set_a(i, i);
}
let mut rng = rand::thread_rng();
// generate the ops that the mutator thread will perform
let write_ops: Vec<MutatorOp> = (0..N_MUTATOR_OPS).map(|_| rng.gen()).collect();
// execute the "main thread", which sometimes snapshots off other threads
let mut all_threads = vec![];
for op in write_ops {
match op {
MutatorOp::WriteOp(w) => w.execute(&mut db),
MutatorOp::LaunchReader {
ops,
check_cancellation,
} => all_threads.push(std::thread::spawn({
let db = db.snapshot();
move || Cancelled::catch(|| db_reader_thread(&db, ops, check_cancellation))
})),
}
}
for thread in all_threads {
thread.join().unwrap().ok();
}
}
|
