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Niko1221
b89bf5947d
A Windows process starts with the I/O priority of the program that started it. Run from a Task Scheduler task, a service, or a terminal that an IDE or coding agent keeps at low priority, the engine inherited Low I/O priority: the reporter measured PLE direct reads about 15x slower, cold prompt reads 3-5x slower and decode 14% slower on the same drive, and the engine blamed the drive. Both engines (strata and strata-dsv41) now read ProcessIoPriority at start and set it to Normal when it is lower (no privilege needed to go from Low to Normal). STRATA_KEEP_IO_PRIORITY=1 leaves it as inherited. The CPU priority class is not touched. New io_priority_test (Windows): started at Low it ends at Normal, started at Normal it is untouched, KEEP leaves Low alone. Tested here: that test passes on Windows; the HIP engine builds. Not tested: the reporter's slowdown itself (needs their drive and a low-priority launcher with an engine run).
44 lines
2.0 KiB
C++
44 lines
2.0 KiB
C++
// io_priority_test (#4733): on Windows a process that starts at Low I/O priority is put back to Normal; elsewhere the call does nothing.
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#include "strata/platform/io_priority.hpp"
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#include <cstdio>
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#include <cstdlib>
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#if defined(_WIN32)
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#include <windows.h>
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static unsigned long io_prio() {
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using Query = LONG(NTAPI*)(HANDLE, ULONG, PVOID, ULONG, PULONG);
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auto q = reinterpret_cast<Query>(reinterpret_cast<void*>(GetProcAddress(GetModuleHandleW(L"ntdll.dll"), "NtQueryInformationProcess")));
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ULONG v = 99, r = 0;
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return q != nullptr && q(GetCurrentProcess(), 33, &v, sizeof v, &r) == 0 ? v : 99;
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}
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static bool set_io_prio(ULONG v) {
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using Set = LONG(NTAPI*)(HANDLE, ULONG, PVOID, ULONG);
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auto s = reinterpret_cast<Set>(reinterpret_cast<void*>(GetProcAddress(GetModuleHandleW(L"ntdll.dll"), "NtSetInformationProcess")));
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return s != nullptr && s(GetCurrentProcess(), 33, &v, sizeof v) == 0;
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}
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#endif
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int main() {
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#if defined(_WIN32)
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int bad = 0;
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// 1. started at Low: back to Normal, and the call reports what it found
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if (!set_io_prio(1)) { std::printf("io_priority_test: SKIP (cannot lower the I/O priority here)\n"); return 77; }
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int was = strata::platform::restore_normal_io_priority(stderr);
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if (was != 1 || io_prio() != 2) { std::printf("FAIL lowered: was=%d now=%lu\n", was, io_prio()); ++bad; }
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// 2. already Normal: untouched, reported as 2
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was = strata::platform::restore_normal_io_priority(nullptr);
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if (was != 2 || io_prio() != 2) { std::printf("FAIL normal: was=%d now=%lu\n", was, io_prio()); ++bad; }
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// 3. STRATA_KEEP_IO_PRIORITY=1 leaves a low value alone
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_putenv("STRATA_KEEP_IO_PRIORITY=1");
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set_io_prio(1);
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was = strata::platform::restore_normal_io_priority(nullptr);
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if (was != -1 || io_prio() != 1) { std::printf("FAIL keep: was=%d now=%lu\n", was, io_prio()); ++bad; }
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std::printf(bad == 0 ? "io_priority_test: OK\n" : "io_priority_test: %d FAILED\n", bad);
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return bad == 0 ? 0 : 1;
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#else
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std::printf("io_priority_test: SKIP (Windows only)\n");
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return 77;
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#endif
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}
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