6be8f234

main: add exponential backoff on Vulkan timeout retries

a73x 2026-04-18 15:25

Commit message

main: add exponential backoff on Vulkan timeout retries

If the driver is genuinely wedged, the timeout-retry loop would spin
at full speed. Track consecutive VkWaitTimeout / VkAcquireTimeout
events and sleep 5ms * N (capped at 100ms) before retrying. Counter
resets on any successful frame.

Closes issue ab6c92f0.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/main.zig

Old		New
@@ -337,6 +337,7 @@ fn runTerminal(alloc: std.mem.Allocator) !void {
337	var render_pending = true;	337	var render_pending = true;
338	var resize_pending = false;	338	var resize_pending = false;
339	var scale_pending = false;	339	var scale_pending = false;
		340	var consecutive_vk_timeouts: u32 = 0;
340		341
341	while (!window.should_close and p.isChildAlive()) {	342	while (!window.should_close and p.isChildAlive()) {
342	const repeat_timeout_ms = remainingRepeatTimeoutMs(keyboard.nextRepeatDeadlineNs());	343	const repeat_timeout_ms = remainingRepeatTimeoutMs(keyboard.nextRepeatDeadlineNs());
@@ -601,6 +602,9 @@ fn runTerminal(alloc: std.mem.Allocator) !void {
601	) catch \|err\| switch (err) {	602	) catch \|err\| switch (err) {
602	error.VkWaitTimeout => {	603	error.VkWaitTimeout => {
603	vk_sync.logVkTimeout(@src(), .atlas);	604	vk_sync.logVkTimeout(@src(), .atlas);
		605	consecutive_vk_timeouts +\|= 1;
		606	const backoff_us: u64 = @min(@as(u64, consecutive_vk_timeouts) * 5_000, 100_000);
		607	std.Thread.sleep(backoff_us * std.time.ns_per_us);
604	render_pending = true;	608	render_pending = true;
605	continue;	609	continue;
606	},	610	},
@@ -696,11 +700,15 @@ fn runTerminal(alloc: std.mem.Allocator) !void {
696	},	700	},
697	error.VkWaitTimeout, error.VkAcquireTimeout => {	701	error.VkWaitTimeout, error.VkAcquireTimeout => {
698	vk_sync.logVkTimeout(@src(), .fence);	702	vk_sync.logVkTimeout(@src(), .fence);
		703	consecutive_vk_timeouts +\|= 1;
		704	const backoff_us: u64 = @min(@as(u64, consecutive_vk_timeouts) * 5_000, 100_000);
		705	std.Thread.sleep(backoff_us * std.time.ns_per_us);
699	render_pending = true;	706	render_pending = true;
700	continue;	707	continue;
701	},	708	},
702	else => return err,	709	else => return err,
703	};	710	};
		711	consecutive_vk_timeouts = 0;
704	frame_timing.gpu_submit_us = usFromTimer(&section_timer);	712	frame_timing.gpu_submit_us = usFromTimer(&section_timer);
705	frame_timing.wait_fences_us = submit_timing.wait_fences_us;	713	frame_timing.wait_fences_us = submit_timing.wait_fences_us;
706	frame_timing.acquire_us = submit_timing.acquire_us;	714	frame_timing.acquire_us = submit_timing.acquire_us;