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Sanitize the high performance counter in Windows

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This avoids to report bad stats.
This commit is contained in:
Andrea Mazzoleni 2017-05-01 15:46:33 +02:00
parent 17bec43be2
commit 0ca3496891
1 changed files with 50 additions and 3 deletions
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53
cmdline/mingw.c
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@ -46,12 +46,24 @@ int exit_sync_needed = 2;
*/
static BOOLEAN (WINAPI* ptr_RtlGenRandom)(PVOID, ULONG);
/**
* Direct access to GetTickCount64().
* This function is available only from Windows Vista.
*/
static ULONGLONG (WINAPI* ptr_GetTickCount64)(void);
/**
* Description of the last error.
* It's stored in the thread local storage.
*/
static pthread_key_t last_error;
/**
* Monotone tick counter
*/
static pthread_mutex_t tick_lock;
static uint64_t tick_last;
/**
* If we are running in Wine.
*/
@ -112,6 +124,12 @@ void os_init(int opt)
exit(EXIT_FAILURE);
}
tick_last = 0;
if (pthread_mutex_init(&tick_lock, 0) != 0) {
log_fatal("Error calling pthread_mutex_init().\n");
exit(EXIT_FAILURE);
}
ntdll = GetModuleHandle("NTDLL.DLL");
if (!ntdll) {
log_fatal("Error loading the NTDLL module.\n");
@ -139,6 +157,9 @@ void os_init(int opt)
/* get pointer to RtlGenRandom, note that it was reported missing in some cases */
ptr_RtlGenRandom = (void*)GetProcAddress(dll_advapi32, "SystemFunction036");
/* get pointer to RtlGenRandom, note that it was reported missing in some cases */
ptr_GetTickCount64 = (void*)GetProcAddress(kernel32, "GetTickCount64");
/* set the thread execution level to avoid sleep */
/* first try for Windows 7 */
if (SetThreadExecutionState(WIN32_ES_CONTINUOUS | WIN32_ES_SYSTEM_REQUIRED | WIN32_ES_AWAYMODE_REQUIRED) == 0) {
@ -154,6 +175,8 @@ void os_done(void)
/* delete the thread local storage for strerror() */
pthread_key_delete(last_error);
pthread_mutex_destroy(&tick_lock);
/* restore the normal execution level */
SetThreadExecutionState(WIN32_ES_CONTINUOUS);
@ -1968,16 +1991,40 @@ size_t windows_direct_size(void)
uint64_t tick(void)
{
LARGE_INTEGER t;
uint64_t r;
if (!QueryPerformanceCounter(&t))
return 0;
/*
* Ensure to return a strict monotone tick counter.
*
* We had reports of invalid stats due faulty High Precision Event Timer.
* See: https://sourceforge.net/p/snapraid/discussion/1677233/thread/a2122fd6/
*/
pthread_mutex_lock(&tick_lock);
return t.QuadPart;
/*
* MSDN 'QueryPerformanceCounter'
* "On systems that run Windows XP or later, the function"
* "will always succeed and will thus never return zero."
*/
r = 0;
if (QueryPerformanceCounter(&t))
r = t.QuadPart;
if (r < tick_last)
r = tick_last;
tick_last = r;
pthread_mutex_unlock(&tick_lock);
return r;
}
uint64_t tick_ms(void)
{
/* GetTickCount64() isn't supported in Windows XP */
if (ptr_GetTickCount64 != 0)
return ptr_GetTickCount64();
return GetTickCount();
}