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add tests for futex #2

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104 changes: 97 additions & 7 deletions lib/std/sync/futex.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ test "futex" {

const Self = @This();
const State = enum(u32) { unset, set };
pub const Lock = @import("./primitives/Mutex.zig").Mutex(Futex);

pub fn init(self: *Self) void {
self.state = .unset;
Expand Down Expand Up @@ -57,7 +58,7 @@ test "futex" {
}

atomic.store(&self.state, .set, .SeqCst);
Futex.notifyOne(@ptrCast(*const u32, &self.state));
Futex.wake(@ptrCast(*const u32, &self.state), @as(u32, 1));
}

pub fn reset(self: *Self) void {
Expand All @@ -68,12 +69,101 @@ test "futex" {
};

inline for (.{
.{os},
.{spin},
.{event},
.{generic.forFutex(os)},
.{generic.forFutex(spin)},
os,
spin,
event,
generic.forFutex(os),
generic.forFutex(spin),
}) |futex| {
// @compileError("TODO: test wait/wake/nanotime");
{
// Simple wait/wake
const Context = struct {
state: State = .unset,
const State = enum(u32) { unset, set };

fn waker(ctx: *@This()) !void {
std.time.sleep(std.time.ns_per_ms * 2);
atomic.store(&ctx.state, .set, .SeqCst);
Futex.wake(@ptrCast(*const u32, &ctx.state), @as(u32, 1));
}

fn waiter(ctx: *@This()) !void {
while (atomic.load(&ctx.state, .SeqCst) == .unset) {
futex.wait(@ptrCast(*const u32, &ctx.state), @enumToInt(State.unset), null) catch unreachable;
}
}
};

var ctx = Context{};
var twait = try std.Thread.spawn(&ctx, Context.waiter);
var twake = try std.Thread.spawn(&ctx, Context.waker);

twait.wait();
twake.wait();
}

{
// Multiple wake
const waiters = 8;

const Context = struct {
state: State = .unset,
const State = enum(u32) { unset, set };

fn waker(ctx: *@This()) !void {
std.time.sleep(std.time.ns_per_ms * 2);
atomic.store(&ctx.state, .set, .SeqCst);
Futex.wake(@ptrCast(*const u32, &ctx.state), @as(u32, waiters));
}

fn waiter(ctx: *@This()) !void {
while (atomic.load(&ctx.state, .SeqCst) == .unset) {
futex.wait(@ptrCast(*const u32, &ctx.state), @enumToInt(State.unset), null) catch unreachable;
}
}
};

var ctx = Context{};
var twaiters: [waiters]*std.Thread = undefined;
for (twaiters) |*waiter| {
waiter.* = try std.Thread.spawn(&ctx, Context.waiter);
}
var twake = try std.Thread.spawn(&ctx, Context.waker);

twake.wait();
for (twaiters) |waiter| {
waiter.wait();
}
}

{
// Timeout
const Context = struct {
state: State = .unset,
const State = enum(u32) { unset, set };

const duration = std.time.ns_per_ms * 2;

fn slowWaker(ctx: *@This()) !void {
std.time.sleep(duration + 1);
atomic.store(&ctx.state, .set, .SeqCst);
Futex.wake(@ptrCast(*const u32, &ctx.state), @as(u32, 1));
}

fn waiter(ctx: *@This()) !void {
while (atomic.load(&ctx.state, .SeqCst) == .unset) {
futex.wait(@ptrCast(*const u32, &ctx.state), @enumToInt(State.unset), duration) catch return;
}
unreachable;
}
};

var ctx = Context{};
var twait = try std.Thread.spawn(&ctx, Context.waiter);
var twake = try std.Thread.spawn(&ctx, Context.slowWaker);

twait.wait();
twake.wait();
}
}
}
2 changes: 1 addition & 1 deletion lib/std/sync/futex/generic.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ const helgrind: ?type = if (builtin.valgrind_support) std.valgrind.helgrind else
pub fn Futex(comptime Event: type) type {
return struct {
const WaitLock = Event.Lock;
const bucket_count = Event.bucket_count;
const bucket_count = if (@hasDecl(Event, "bucket_count")) Event.bucket_count else 1024;

const WaitBucket = struct {
lock: WaitLock = .{},
Expand Down