Every direct memory allocation had a memfd of its own, so each one the
GPU used became its own udmabuf and its own imported buffer object. An
imported buffer object cannot be always valid in the GPU VM: amdgpu
validates every one of them at every command submission. PPSA14632
(LEGO Horizon Adventures) imports about 7000 allocations, 5800 of them
64 KiB, and each vkQueueSubmit took about 2.3 ms (5 s per 10 s, held
under the GPU mutex). A standalone test shows the cost follows the
count of imported dma-buf buffer objects, not their size or the count
of ordinary allocations.
- libkernel: on Linux all direct memory lives in one sparse memfd of
DIRECT_MEMORY_SIZE, at file offset = physical address
(PhysicalBacking keeps the file and its offset; SharedBacking returns
that offset). A range allocated again is zeroed through a temporary
mapping, as the old per-allocation memfd was.
- Driver: an import of shared direct memory that lies inside one
64 MiB chunk of the file binds its own VkBuffer into that chunk's
memory, one udmabuf import per chunk (HostImport::chunk holds it, so
it lives until the last buffer bound to it retires). Ranges that
cross a chunk or do not meet the buffer alignment are imported alone
as before.
On PPSA14632 vkQueueSubmit drops from about 2400 us to 46 us on
average, the GPU idles 36 ms instead of 172 ms per present, and
presents go from about 40 to 80-97 per 10 s.
Released direct memory stays committed in the file (see
TechnicalDebt.md): a live chunk import pins its pages.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
macOS has no counterpart to userfaultfd write-protect or
MEM_WRITE_WATCH, so GuestWriteWatch had no backend there and the driver
re-read every guest buffer on each use.
The macOS backend write-protects watched pages. The first write to a
page faults, the SIGBUS/SIGSEGV handler records the page and restores
its protection, and Collect reports the recorded pages and protects
them again. A page is protected before its record is cleared, under the
lock the handler takes, so a write that lands in between is recorded.
The lock hands out turns in order: an unfair one starved writers under
Rosetta.
The protection is real, which adds three entry points:
- GuestWriteWatchBeginHostWrite/EndHostWrite lift it around a system
call that writes guest memory, which would otherwise fail with
EFAULT. GuestArena::HostWrite calls them, as it calls the Windows
equivalent.
- GuestWriteWatchProtectionChanged tells the watch the protection given
to watched pages by mprotect or a new mapping.
- GuestWriteWatchProtection reports that protection, since a watched
page is read-only between a collection and the next write.
Register keeps the recorded protection of a page it already watches:
read from the kernel it would be the watch's own read-only protection,
and the page would never be watched again.
The tests build without the prx libraries and run natively and through
Rosetta.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Retain an immutable decoded program and structured control flow while
preparing the registration variants for one shader.
Match owned code, stage and the complete SWAPPC inputs before reuse.
Translate and plan each variant separately using its current inputs.
Keep cache keys and persisted artifact layouts unchanged.
Provide a cache-neutral off switch for controlled comparisons.
Cover identity, lifetime, failed replacements and variant equivalence.
The Windows runner has no Vulkan driver, so the VideoOut window tests skip there for the same reason; check_skips.py
only accepted agc* skips in that job.
Main's Linux job fails since #1028 and #1714: guest_video_out_resolution_status aborts when SDL's offscreen
driver has no Vulkan window, and check_skips.py rejects the skips of guest_video_out_wqhd_detection and the
flip tests because "no display" is not among the device limitations it accepts.
The resolution status test now skips with code 77 like its wqhd sibling, the flip tests print the same skip
reason, and check_skips.py accepts "no display" as a device limitation. ANYPS5_REQUIRE_DISPLAY still turns
the skip into a failure.
AI-assisted: yes. Full current-main project build passed. Seven focused Windows tests pass; four shader tests also pass in full and none optimization modes with actual Vulkan execution required. Updated Linux and title runs remain pending.
AI-assisted: yes. Full current-main project build passed. Seven focused Windows tests pass; four shader tests also pass in full and none optimization modes with actual Vulkan execution required. Updated Linux and title runs remain pending.
Hannah Lyons