util.c

/*
 * clockperf
 *
 * Copyright (c) 2016-2021, Steven Noonan <steven@uplinklabs.net>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include "prefix.h"
#include "util.h"

#ifdef TARGET_OS_WINDOWS
#ifndef CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
#define CREATE_WAITABLE_TIMER_HIGH_RESOLUTION 0x00000002
#endif

static HANDLE s_timer;

typedef LONG NTSTATUS;
typedef NTSTATUS (NTAPI *NtSetTimerResolution)(ULONG DesiredResolution, BOOLEAN SetResolution, PULONG CurrentResolution);
typedef NTSTATUS (NTAPI *NtQueryTimerResolution)(PULONG MinimumResolution, PULONG MaximumResolution, PULONG CurrentResolution);
#endif

int thread_sleep(unsigned long usec)
{
#if defined(TARGET_OS_WINDOWS)
    if (s_timer) {
        long long nt_ticks = usec * 10;
        LARGE_INTEGER li;
        li.QuadPart = -nt_ticks;
        if(!SetWaitableTimer(s_timer, &li, 0, NULL, NULL, FALSE)){
            return 1;
        }
        WaitForSingleObject(s_timer, INFINITE);
    } else {
        usec /= 1000;
        if (usec < 1)
            usec = 1;
        Sleep(usec);
    }
    return 0;
#else
    return usleep(usec);
#endif
}

void timers_init(void)
{
#ifdef TARGET_OS_WINDOWS
    NtSetTimerResolution pNtSetTimerResolution;
    NtQueryTimerResolution pNtQueryTimerResolution;

    HMODULE hNtDll = GetModuleHandleA("ntdll.dll");
    if (!hNtDll)
        return;

    pNtSetTimerResolution = (NtSetTimerResolution)GetProcAddress(hNtDll, "NtSetTimerResolution");
    pNtQueryTimerResolution = (NtQueryTimerResolution)GetProcAddress(hNtDll, "NtQueryTimerResolution");
    if (pNtSetTimerResolution && pNtQueryTimerResolution)
    {
        NTSTATUS result;
        ULONG ulMinimum = 0, ulMaximum = 0, ulCurrent = 0;

        result = pNtQueryTimerResolution(&ulMinimum, &ulMaximum, &ulCurrent);
        if (result != ERROR_SUCCESS)
            return;

        result = pNtSetTimerResolution(ulMaximum, TRUE, &ulCurrent);
        if (result != ERROR_SUCCESS)
            return;

        result = pNtQueryTimerResolution(&ulMinimum, &ulMaximum, &ulCurrent);
        if (result != ERROR_SUCCESS)
            return;
    }

    /* Disabled for now, need to understand why a waitable timer would fire too
     * early (e.g. run with --drift and you'll see it fire multiple times per
     * second)
     */
#if 0
    s_timer = CreateWaitableTimerEx(
            NULL, NULL,
            CREATE_WAITABLE_TIMER_MANUAL_RESET | CREATE_WAITABLE_TIMER_HIGH_RESOLUTION,
            TIMER_ALL_ACCESS);
#endif
#endif
}

void timers_destroy(void)
{
#ifdef TARGET_OS_WINDOWS
    if (s_timer)
        CloseHandle(s_timer);
    s_timer = NULL;
#endif
}