Commit 238de05d2c
Changed files (1)
lib
std
lib/std/Io/EventLoop.zig
@@ -5,6 +5,7 @@ const Allocator = std.mem.Allocator;
const Io = std.Io;
const EventLoop = @This();
const Alignment = std.mem.Alignment;
+const IoUring = std.os.linux.IoUring;
gpa: Allocator,
mutex: std.Thread.Mutex,
@@ -13,18 +14,27 @@ queue: std.DoublyLinkedList(void),
free: std.DoublyLinkedList(void),
main_context: Context,
exit_awaiter: ?*Fiber,
-idle_count: usize,
threads: std.ArrayListUnmanaged(Thread),
+/// 1 bit per thread, same order as `thread_index`.
+idle_iourings: []usize,
-threadlocal var current_idle_context: *Context = undefined;
-threadlocal var current_context: *Context = undefined;
+threadlocal var thread_index: u32 = undefined;
/// Empirically saw 10KB being used by the self-hosted backend for logging.
const idle_stack_size = 32 * 1024;
+const io_uring_entries = 64;
+
const Thread = struct {
thread: std.Thread,
idle_context: Context,
+ current_idle_context: *Context,
+ current_context: *Context,
+ io_uring: IoUring,
+
+ fn currentFiber(thread: *Thread) *Fiber {
+ return @fieldParentPtr("context", thread.current_context);
+ }
};
const Fiber = struct {
@@ -83,16 +93,25 @@ pub fn io(el: *EventLoop) Io {
.vtable = &.{
.@"async" = @"async",
.@"await" = @"await",
+ .createFile = createFile,
+ .openFile = openFile,
+ .closeFile = closeFile,
+ .read = read,
+ .write = write,
},
};
}
-pub fn init(el: *EventLoop, gpa: Allocator) error{OutOfMemory}!void {
- const threads_bytes = ((std.Thread.getCpuCount() catch 1) -| 1) * @sizeOf(Thread);
+pub fn init(el: *EventLoop, gpa: Allocator) !void {
+ const n_threads: usize = @max((std.Thread.getCpuCount() catch 1), 1);
+ const threads_bytes = n_threads * @sizeOf(Thread);
const idle_context_offset = std.mem.alignForward(usize, threads_bytes, @alignOf(Context));
const idle_stack_end_offset = std.mem.alignForward(usize, idle_context_offset + idle_stack_size, std.heap.page_size_max);
const allocated_slice = try gpa.alignedAlloc(u8, @max(@alignOf(Thread), @alignOf(Context)), idle_stack_end_offset);
errdefer gpa.free(allocated_slice);
+ const idle_iourings = try gpa.alloc(usize, (n_threads + @bitSizeOf(usize) - 1) / @bitSizeOf(usize));
+ errdefer gpa.free(idle_iourings);
+ @memset(idle_iourings, 0);
el.* = .{
.gpa = gpa,
.mutex = .{},
@@ -101,9 +120,11 @@ pub fn init(el: *EventLoop, gpa: Allocator) error{OutOfMemory}!void {
.free = .{},
.main_context = undefined,
.exit_awaiter = null,
- .idle_count = 0,
.threads = .initBuffer(@ptrCast(allocated_slice[0..threads_bytes])),
+ .idle_iourings = idle_iourings,
};
+ const main_thread = el.threads.addOneAssumeCapacity();
+ main_thread.io_uring = try IoUring.init(io_uring_entries, 0);
const main_idle_context: *Context = @alignCast(std.mem.bytesAsValue(Context, allocated_slice[idle_context_offset..][0..@sizeOf(Context)]));
const idle_stack_end: [*]align(@max(@alignOf(Thread), @alignOf(Context))) usize = @alignCast(@ptrCast(allocated_slice[idle_stack_end_offset..].ptr));
(idle_stack_end - 1)[0..1].* = .{@intFromPtr(el)};
@@ -113,9 +134,9 @@ pub fn init(el: *EventLoop, gpa: Allocator) error{OutOfMemory}!void {
.rip = @intFromPtr(&mainIdleEntry),
};
std.log.debug("created main idle {*}", .{main_idle_context});
- current_idle_context = main_idle_context;
+ main_thread.current_idle_context = main_idle_context;
std.log.debug("created main {*}", .{&el.main_context});
- current_context = &el.main_context;
+ main_thread.current_context = &el.main_context;
}
pub fn deinit(el: *EventLoop) void {
@@ -125,14 +146,21 @@ pub fn deinit(el: *EventLoop) void {
const free_fiber: *Fiber = @alignCast(@fieldParentPtr("queue_node", free_node));
el.gpa.free(free_fiber.allocatedSlice());
}
- const idle_context_offset = std.mem.alignForward(usize, el.threads.items.len * @sizeOf(Thread), @alignOf(Context));
+ const idle_context_offset = std.mem.alignForward(usize, el.threads.capacity * @sizeOf(Thread), @alignOf(Context));
const idle_stack_end = std.mem.alignForward(usize, idle_context_offset + idle_stack_size, std.heap.page_size_max);
const allocated_ptr: [*]align(@max(@alignOf(Thread), @alignOf(Context))) u8 = @alignCast(@ptrCast(el.threads.items.ptr));
- for (el.threads.items) |*thread| thread.thread.join();
+ for (el.threads.items[1..]) |*thread| thread.thread.join();
el.gpa.free(allocated_ptr[0..idle_stack_end]);
}
-fn yield(el: *EventLoop, optional_fiber: ?*Fiber, register_awaiter: ?*?*Fiber) void {
+const PendingTask = union(enum) {
+ none,
+ register_awaiter: *?*Fiber,
+ io_uring_submit: *IoUring,
+};
+
+fn yield(el: *EventLoop, optional_fiber: ?*Fiber, pending_task: PendingTask) void {
+ const thread: *Thread = &el.threads.items[thread_index];
const ready_context: *Context = ready_context: {
const ready_fiber: *Fiber = optional_fiber orelse if (ready_node: {
el.mutex.lock();
@@ -141,13 +169,13 @@ fn yield(el: *EventLoop, optional_fiber: ?*Fiber, register_awaiter: ?*?*Fiber) v
}) |ready_node|
@alignCast(@fieldParentPtr("queue_node", ready_node))
else
- break :ready_context current_idle_context;
+ break :ready_context thread.current_idle_context;
break :ready_context &ready_fiber.context;
};
const message: SwitchMessage = .{
- .prev_context = current_context,
+ .prev_context = thread.current_context,
.ready_context = ready_context,
- .register_awaiter = register_awaiter,
+ .pending_task = pending_task,
};
std.log.debug("switching from {*} to {*}", .{ message.prev_context, message.ready_context });
contextSwitch(&message).handle(el);
@@ -156,6 +184,11 @@ fn yield(el: *EventLoop, optional_fiber: ?*Fiber, register_awaiter: ?*?*Fiber) v
fn schedule(el: *EventLoop, fiber: *Fiber) void {
el.mutex.lock();
el.queue.append(&fiber.queue_node);
+ //for (el.idle_iourings) |*int| {
+ // const idler_subset = @atomicLoad(usize, int, .unordered);
+ // if (idler_subset == 0) continue;
+ //
+ //}
if (el.idle_count > 0) {
el.mutex.unlock();
el.cond.signal();
@@ -167,7 +200,7 @@ fn schedule(el: *EventLoop, fiber: *Fiber) void {
thread.thread = std.Thread.spawn(.{
.stack_size = idle_stack_size,
.allocator = el.gpa,
- }, threadEntry, .{ el, thread }) catch {
+ }, threadEntry, .{ el, el.threads.items.len - 1 }) catch {
el.threads.items.len -= 1;
return;
};
@@ -187,38 +220,61 @@ fn mainIdle(el: *EventLoop, message: *const SwitchMessage) callconv(.withStackAl
unreachable; // switched to dead fiber
}
-fn threadEntry(el: *EventLoop, thread: *Thread) void {
+fn threadEntry(el: *EventLoop, index: usize) void {
+ thread_index = index;
+ const thread: *Thread = &el.threads.items[index];
std.log.debug("created thread idle {*}", .{&thread.idle_context});
- current_idle_context = &thread.idle_context;
- current_context = &thread.idle_context;
+ thread.io_uring = IoUring.init(io_uring_entries, 0) catch |err| {
+ std.log.warn("exiting worker thread during init due to io_uring init failure: {s}", .{@errorName(err)});
+ return;
+ };
+ thread.current_idle_context = &thread.idle_context;
+ thread.current_context = &thread.idle_context;
_ = el.idle();
}
fn idle(el: *EventLoop) *Fiber {
+ const thread: *Thread = &el.threads.items[thread_index];
+ // The idle fiber only runs on one thread.
+ const iou = &thread.io_uring;
+ var cqes_buffer: [io_uring_entries]std.os.linux.io_uring_cqe = undefined;
+
while (true) {
el.yield(null, null);
if (@atomicLoad(?*Fiber, &el.exit_awaiter, .acquire)) |exit_awaiter| {
el.cond.broadcast();
return exit_awaiter;
}
- el.mutex.lock();
- defer el.mutex.unlock();
- el.idle_count += 1;
- defer el.idle_count -= 1;
- el.cond.wait(&el.mutex);
+ // TODO add uring to bit set
+ const n = iou.copy_cqes(&cqes_buffer, 1) catch @panic("TODO handle copy_cqes error");
+ const cqes = cqes_buffer[0..n];
+ for (cqes) |cqe| {
+ const fiber: *Fiber = @ptrFromInt(cqe.user_data);
+ const res: *i32 = @ptrCast(@alignCast(fiber.resultPointer()));
+ res.* = cqe.res;
+ el.schedule(fiber);
+ }
}
}
const SwitchMessage = extern struct {
prev_context: *Context,
ready_context: *Context,
- register_awaiter: ?*?*Fiber,
+ pending_task: PendingTask,
fn handle(message: *const SwitchMessage, el: *EventLoop) void {
- current_context = message.ready_context;
- if (message.register_awaiter) |awaiter| {
- const prev_fiber: *Fiber = @alignCast(@fieldParentPtr("context", message.prev_context));
- if (@atomicRmw(?*Fiber, awaiter, .Xchg, prev_fiber, .acq_rel) == Fiber.finished) el.schedule(prev_fiber);
+ const thread: *Thread = &el.threads.items[thread_index];
+ thread.current_context = message.ready_context;
+ switch (message.pending_task) {
+ .none => {},
+ .register_awaiter => |awaiter| {
+ const prev_fiber: *Fiber = @alignCast(@fieldParentPtr("context", message.prev_context));
+ if (@atomicRmw(?*Fiber, awaiter, .Xchg, prev_fiber, .acq_rel) == Fiber.finished) el.schedule(prev_fiber);
+ },
+ .io_uring_submit => |iou| {
+ _ = iou.flush_sq();
+ // TODO: determine whether this return value should be used
+ },
}
}
};
@@ -357,3 +413,132 @@ pub fn @"await"(userdata: ?*anyopaque, any_future: *std.Io.AnyFuture, result: []
@memcpy(result, future_fiber.resultPointer());
event_loop.recycle(future_fiber);
}
+
+pub fn createFile(userdata: ?*anyopaque, dir: std.fs.Dir, sub_path: []const u8, flags: std.fs.File.CreateFlags) std.fs.File.OpenError!std.fs.File {
+ _ = userdata;
+ _ = dir;
+ _ = sub_path;
+ _ = flags;
+ @panic("TODO");
+}
+
+pub fn openFile(userdata: ?*anyopaque, dir: std.fs.Dir, sub_path: []const u8, flags: std.fs.File.OpenFlags) std.fs.File.OpenError!std.fs.File {
+ const el: *EventLoop = @ptrCast(@alignCast(userdata));
+
+ const posix = std.posix;
+ const sub_path_c = try posix.toPosixPath(sub_path);
+
+ var os_flags: posix.O = .{
+ .ACCMODE = switch (flags.mode) {
+ .read_only => .RDONLY,
+ .write_only => .WRONLY,
+ .read_write => .RDWR,
+ },
+ };
+
+ if (@hasField(posix.O, "CLOEXEC")) os_flags.CLOEXEC = true;
+ if (@hasField(posix.O, "LARGEFILE")) os_flags.LARGEFILE = true;
+ if (@hasField(posix.O, "NOCTTY")) os_flags.NOCTTY = !flags.allow_ctty;
+
+ // Use the O locking flags if the os supports them to acquire the lock
+ // atomically.
+ const has_flock_open_flags = @hasField(posix.O, "EXLOCK");
+ if (has_flock_open_flags) {
+ // Note that the NONBLOCK flag is removed after the openat() call
+ // is successful.
+ switch (flags.lock) {
+ .none => {},
+ .shared => {
+ os_flags.SHLOCK = true;
+ os_flags.NONBLOCK = flags.lock_nonblocking;
+ },
+ .exclusive => {
+ os_flags.EXLOCK = true;
+ os_flags.NONBLOCK = flags.lock_nonblocking;
+ },
+ }
+ }
+ const have_flock = @TypeOf(posix.system.flock) != void;
+
+ if (have_flock and !has_flock_open_flags and flags.lock != .none) {
+ @panic("TODO");
+ }
+
+ if (has_flock_open_flags and flags.lock_nonblocking) {
+ @panic("TODO");
+ }
+
+ const thread: *Thread = &el.threads.items[thread_index];
+ const iou = &thread.io_uring;
+ const sqe = getSqe(iou);
+ const fiber = thread.currentFiber();
+
+ sqe.prep_openat(dir.fd, &sub_path_c, os_flags, 0);
+ sqe.user_data = @intFromPtr(fiber);
+
+ el.yield(null, .{ .io_uring_submit = iou });
+
+ const result: *i32 = @alignCast(@ptrCast(fiber.resultPointer()[0..@sizeOf(posix.fd_t)]));
+ const rc = result.*;
+ switch (errno(rc)) {
+ .SUCCESS => return .{ .handle = rc },
+ .INTR => @panic("TODO is this reachable?"),
+ .CANCELED => @panic("TODO figure out how this error code fits into things"),
+
+ .FAULT => unreachable,
+ .INVAL => return error.BadPathName,
+ .BADF => unreachable,
+ .ACCES => return error.AccessDenied,
+ .FBIG => return error.FileTooBig,
+ .OVERFLOW => return error.FileTooBig,
+ .ISDIR => return error.IsDir,
+ .LOOP => return error.SymLinkLoop,
+ .MFILE => return error.ProcessFdQuotaExceeded,
+ .NAMETOOLONG => return error.NameTooLong,
+ .NFILE => return error.SystemFdQuotaExceeded,
+ .NODEV => return error.NoDevice,
+ .NOENT => return error.FileNotFound,
+ .NOMEM => return error.SystemResources,
+ .NOSPC => return error.NoSpaceLeft,
+ .NOTDIR => return error.NotDir,
+ .PERM => return error.PermissionDenied,
+ .EXIST => return error.PathAlreadyExists,
+ .BUSY => return error.DeviceBusy,
+ .OPNOTSUPP => return error.FileLocksNotSupported,
+ .AGAIN => return error.WouldBlock,
+ .TXTBSY => return error.FileBusy,
+ .NXIO => return error.NoDevice,
+ else => |err| return posix.unexpectedErrno(err),
+ }
+
+ return .{ .handle = result.* };
+}
+
+fn errno(signed: i32) std.posix.E {
+ const int = if (signed > -4096 and signed < 0) -signed else 0;
+ return @enumFromInt(int);
+}
+
+fn getSqe(iou: *IoUring) *std.os.linux.io_uring_sqe {
+ return iou.get_sqe() catch @panic("TODO: handle submission queue full");
+}
+
+pub fn closeFile(userdata: ?*anyopaque, file: std.fs.File) void {
+ _ = userdata;
+ _ = file;
+ @panic("TODO");
+}
+
+pub fn read(userdata: ?*anyopaque, file: std.fs.File, buffer: []u8) std.fs.File.ReadError!usize {
+ _ = userdata;
+ _ = file;
+ _ = buffer;
+ @panic("TODO");
+}
+
+pub fn write(userdata: ?*anyopaque, file: std.fs.File, buffer: []const u8) std.fs.File.WriteError!usize {
+ _ = userdata;
+ _ = file;
+ _ = buffer;
+ @panic("TODO");
+}