ed
a9335928c7
8-post thread on NV-specific 1-deep swap with IMMEDIATE presentation,
after previous AMD-tuned impl stopped working. One descriptor set
always bound (resources static after init). Dropped
VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT
('god awful naming length') to avoid NV indirection perf hit.
2700 lines of engine, embedded headers, one-file compile. 0.25 sec
hot-load on NV dGPU: 4 MiB 'cart' file from pagecache, 512 MiB GPU
buffer, all PSOs, image alloc, command buffer copy+clear. Load-time
parallelism: {instance create, cart map, TLB warming by walking pages,
window bringup} = 0.08 sec. After VK device, signal background SPIR-V
load while building descriptor set layout, then PSO compile
parallel. Earliest documented use of 'cart file' term - 9 months
before the Aug 2025 public announcement.
2.8 KiB
title, author, handle, post_url, post_id, timestamp, post_count, reply_count, repost_count, like_count, view_count
| title | author | handle | post_url | post_id | timestamp | post_count | reply_count | repost_count | like_count | view_count |
|---|---|---|---|---|---|---|---|---|---|---|
| After VK device is open, I signal a background thread to load the SPIR-V module, | NOTimothyLottes | @NOTimothyLottes | https://x.com/NOTimothyLottes/status/1858715434436227544 | 1858715434436227544 | 2024-11-19 03:34:27 | 8 | 0 | 0 | 2 | 424 |
@NOTimothyLottes — After VK device is open, I signal a background thread to load the SPIR-V module,
Post 1 (2024-11-19 03:10:28)
Working towards a new bring up of front-buffering on NV via VK. My last implementation had been tuned on AMD and didn't work on NV any more. NV does seem to accept a 1-deep swap with IMMEDIATE presentation at least on latest drivers, so that is a good start.
Post 2 (2024-11-19 03:13:21) — reply to Post 1
Since my image resources are static after init time, only swap images change when the driver kills the swap chain (which once upon a time seemed to happen on ALT+TAB maybe). So it's one descriptor set always bound.
Post 3 (2024-11-19 03:15:43) — reply to Post 2
Stopped using VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT (god awful naming length people), because I think it could be a perf hit on NV due to extra indirection. NV driver is free to bake down the single set now before the command buffer is sent over.
Post 4 (2024-11-19 03:21:26) — reply to Post 3
At this stage, to the point of having everything loaded and swap chain created, it's 2700 lines of engine code. That includes embedding headers (no external includes), so it's a one file compile. People claim rolling your own engine is hard? Not really if you keep it focused.
Post 5 (2024-11-19 03:26:46) — reply to Post 4
So far it's a 0.25 sec hot load time on this NV dGPU laptop. Includes mapping a 4 MiB 'cart' file from pagecache, doing a 512 MiB buffer for GPU usage, hits on all PSOs, allocating some images, and kicking the command buffer that copies in the cart, and clears everything.
Post 6 (2024-11-19 03:29:11) — reply to Post 5
Everything at load-time is multi-threaded to try to minimize start to in-game time. This is in sharp contrast to runtime where the only multi-threading being used is to separate things that are blocking.
Post 7 (2024-11-19 03:32:22) — reply to Post 6
I get some utility on parallelizing {vulkan instance creation, mapping the cart file, warming the TLBs by walking all the pages, bringing up the window} it's about 0.08 seconds in at that point
Post 8 (2024-11-19 03:34:27) — reply to Post 7
After VK device is open, I signal a background thread to load the SPIR-V module, while building the descriptor set layout, which then unblocks PSO compile on background threads. And the rest of the VK setup runs in parallel. Working towards swap creation.