On an Intel CPU with P-cores and E-cores a thread on an E-core runs at about 60% of a P-core's speed, and the frame
waits for its slowest critical thread. The game's main thread, the thread that presents, and the vk replay, recorder
and present threads now select the CPU sets of the P-core logical processors the process affinity allows. Nothing is
selected on a CPU with one efficiency class or when the affinity leaves only one kind of core. TOTK_PCORE=0 turns it
off; "power:" log lines say what was selected and which threads took it. LAS Recomp does the same for its game,
render and vsync threads.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The perf line's "bound" said cpu at 640x360 on a Ryzen 5 4600G (Vega 7, RADV) and also at 1600x900, where lowering the
resolution showed the GPU held the frame back; the GPU busy time alone cannot tell the two apart. With
VK_KHR/EXT_calibrated_timestamps the GPU timestamps of each part go on the CPU clock (QPC on Windows, CLOCK_MONOTONIC
elsewhere), each part records when it was handed to vkQueueSubmit2, and a third perf line splits the gap before each
timed part: submitted after the previous part ended (the GPU waited for the replay or the game) or already queued
(untimed uploads and presents, or a wait). It also gives the gaps over 0.5 ms, the longest one and the mean time from
submit to start.
On the 4600G at 640x360 (44 fps) it reads 11.3 ms idle a frame, 10.3 ms of it waiting for the next submission, in 3-4
gaps of up to 8 ms, with the replay at 16 ms a frame: the GPU starves behind the replay. Without the extension, or when
the driver refuses the domain pair, the line is left out. Only TOTK_TRACE=perf and the full overlay time the GPU.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Shared runtime code now goes through runtime/platform/platform.h, implemented by platform/win32.c and a new
platform/linux.c: futex locks, a userfaultfd and PAGEMAP_SCAN write watch, signal-based async preemption, our own
fiber switch, and a SIGSEGV handler for the thaw and crash hooks. The window, input, menu and software keyboard get
SDL3 back ends beside the Win32 ones, with the swapchain (gfx_present.c) and input merging (input.c) shared. SHA-256
replaces BCrypt, ELF builds get their own override sections, and the build tools gain Linux branches.
On Linux the selftest and the gfx-abi, astc, nvn and window probes pass. probe-vkmem still fails: imported guest
memory cannot be write-watched on Linux, which the shadow buffers in vk_memory.c will address.
