mpv/osdep/timer-win32.c

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/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <windows.h>
#include <winternl.h>
#include <ntstatus.h>
#include <mmsystem.h>
#include <stdlib.h>
#include <versionhelpers.h>
#include "timer.h"
#include "config.h"
static LARGE_INTEGER perf_freq;
static int64_t hires_max = MP_TIME_MS_TO_NS(50);
static int64_t hires_res = MP_TIME_MS_TO_NS(1);
// NtSetTimerResolution allows setting the timer resolution to less than 1 ms.
// Resolutions are specified in 100-ns units.
// If Set is TRUE, set the RequestedResolution. Otherwise, return to the previous resolution.
NTSTATUS NTAPI NtSetTimerResolution(ULONG RequestedResolution, BOOLEAN Set, PULONG ActualResolution);
// Acquire the valid timer resolution range.
NTSTATUS NTAPI NtQueryTimerResolution(PULONG MinimumResolution, PULONG MaximumResolution, PULONG ActualResolution);
int64_t mp_start_hires_timers(int64_t wait_ns)
{
#if !HAVE_UWP
ULONG actual_res = 0;
// policy: request hires_res resolution if wait < hires_max ns
if (wait_ns > 0 && wait_ns <= hires_max &&
NtSetTimerResolution(hires_res / 100, TRUE, &actual_res) == STATUS_SUCCESS)
{
return hires_res;
}
#endif
return 0;
}
void mp_end_hires_timers(int64_t res_ns)
{
#if !HAVE_UWP
ULONG actual_res = 0;
if (res_ns > 0)
NtSetTimerResolution(res_ns / 100, FALSE, &actual_res);
#endif
}
void mp_sleep_ns(int64_t ns)
{
if (ns < 0)
return;
int64_t hrt = mp_start_hires_timers(ns);
#ifndef CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
#define CREATE_WAITABLE_TIMER_HIGH_RESOLUTION 0x2
#endif
HANDLE timer = CreateWaitableTimerEx(NULL, NULL,
CREATE_WAITABLE_TIMER_HIGH_RESOLUTION,
TIMER_ALL_ACCESS);
// CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is supported in Windows 10 1803+,
// retry without it.
if (!timer)
timer = CreateWaitableTimerEx(NULL, NULL, 0, TIMER_ALL_ACCESS);
if (!timer)
goto end;
// Time is expected in 100 nanosecond intervals.
// Negative values indicate relative time.
LARGE_INTEGER time = (LARGE_INTEGER){ .QuadPart = -(ns / 100) };
if (!SetWaitableTimer(timer, &time, 0, NULL, NULL, 0))
goto end;
if (WaitForSingleObject(timer, INFINITE) != WAIT_OBJECT_0)
goto end;
end:
if (timer)
CloseHandle(timer);
mp_end_hires_timers(hrt);
}
uint64_t mp_raw_time_ns(void)
{
LARGE_INTEGER perf_count;
QueryPerformanceCounter(&perf_count);
// Convert QPC units (1/perf_freq seconds) to nanoseconds. This will work
// without overflow because the QPC value is guaranteed not to roll-over
// within 100 years, so perf_freq must be less than 2.9*10^9.
return perf_count.QuadPart / perf_freq.QuadPart * UINT64_C(1000000000) +
perf_count.QuadPart % perf_freq.QuadPart * UINT64_C(1000000000) / perf_freq.QuadPart;
}
void mp_raw_time_init(void)
{
QueryPerformanceFrequency(&perf_freq);
#if !HAVE_UWP
ULONG min_res, max_res, actual_res;
if (NtQueryTimerResolution(&min_res, &max_res, &actual_res) != STATUS_SUCCESS) {
min_res = 156250;
max_res = 10000;
}
// allow (undocumented) control of all the High Res Timers parameters,
// for easier experimentation and diagnostic of bug reports.
const char *v;
char *end;
// 1..1000 ms max timetout for hires (used in "perwait" mode)
if ((v = getenv("MPV_HRT_MAX"))) {
int64_t hmax = strtoll(v, &end, 10);
if (*end == '\0' && hmax >= MP_TIME_MS_TO_NS(1) && hmax <= MP_TIME_MS_TO_NS(1000))
hires_max = hmax;
}
// hires resolution clamped by the available resolution range (not used in "never" mode)
if ((v = getenv("MPV_HRT_RES"))) {
int64_t res = strtoll(v, &end, 10);
if (*end == '\0' && res >= max_res * INT64_C(100) && res <= min_res * INT64_C(100))
hires_res = res;
}
// "always"/"never"/"perwait" (or "auto" - same as unset)
if (!(v = getenv("MPV_HRT")) || !strcmp(v, "auto"))
v = IsWindows10OrGreater() ? "perwait" : "always";
if (!strcmp(v, "perwait")) {
// no-op, already per-wait
} else if (!strcmp(v, "never")) {
hires_max = 0;
} else { // "always" or unknown value
mp_start_hires_timers(hires_res);
hires_max = 0;
}
#endif
}