[PATCH 0/1] MR4205: user32/tests: Improve timer measurement method.

[Esme Povirk (＠madewokherd)]

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55786

This changes the way we measure minimum timeouts in user32:msg tests.

Currently, it's done by using GetTickCount() to wait approximately 1 second (since GetTickCount() is approximate) and counting the number of times the timer fires in that second. On Wine, a range of 91-109 (equivalent to 9.17-10.98 ms) is accepted, and on Windows a range of 33-74 is additionally accepted (equivalent to 13.51-30.3 ms). (That wide range of Windows timings is obfuscated by presenting it as accepting 43 or 64 counts, each +/- 10, but those ranges actually touch.)

With the patch, we instead wait for the timer to fire 500 times (approximately 5 seconds on Wine, 8 seconds on Windows; I tried 100 times as earlier but didn't get as consistent results with it), calculate the delay between each time it fires using QueryPerformanceCounter, and take the median delay. On the test bot, all my results with this method were within 0.15 ms of the expected values, and most were within 0.05 ms. I'm using a maximum error of 1 ms, which is slightly more forgiving than before.

I'm hoping this cuts down on the CI failures in these tests, but I have no way of knowing for sure.

[PATCH 1/1] user32/tests: Improve timer measurement method.

[Esme Povirk]

From: Esme Povirk

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55786
---
 dlls/user32/tests/msg.c | 106 +++++++++++++++++++++++++++-------------
 1 file changed, 71 insertions(+), 35 deletions(-)

diff --git a/dlls/user32/tests/msg.c b/dlls/user32/tests/msg.c
index 07df7d5cb86..9478ab153c4 100644
--- a/dlls/user32/tests/msg.c
+++ b/dlls/user32/tests/msg.c
@@ -11548,20 +11548,67 @@ static VOID CALLBACK tfunc(HWND hwnd, UINT uMsg, UINT_PTR id, DWORD dwTime)
 {
 }

-#define TIMER_ID               0x19
-#define TIMER_COUNT_EXPECTED   100
-#define TIMER_COUNT_TOLERANCE  10
+#define TIMER_ID                 0x19
+#define TIMER_COUNT              500 /* 499 samples */
+#define TIMER_DURATION_EXPECTED  10000 /* 10 ms */
+#define TIMER_DURATION_ALT       15600 /* 15.6 ms */
+#define TIMER_DURATION_TOLERANCE 1000 /* 1 ms */

static int count = 0;
-static void CALLBACK callback_count(HWND hwnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime)
+static ULONGLONG timer_ticks[TIMER_COUNT];
+static int timer_duration = 0;
+
+static int compare_ulonglong(const void *a, const void *b)
 {
+    ULONGLONG la, lb;
+    la = *(ULONGLONG*)a;
+    lb = *(ULONGLONG*)b;
+    return (la > lb) - (la < lb);
+}
+
+static void timer_fired(void)
+{
+    if (count < TIMER_COUNT)
+    {
+        LARGE_INTEGER performance_counter;
+        BOOL ret;
+
+        ret = QueryPerformanceCounter(&performance_counter);
+        ok(ret, "QueryPerformanceCounter failed\n");
+
+        timer_ticks[count] = performance_counter.QuadPart;
+    }
+
     count++;
+
+    if (count == TIMER_COUNT)
+    {
+        LARGE_INTEGER performance_frequency;
+        BOOL ret;
+
+        /* calculate durations */
+        for (int i=0; i < TIMER_COUNT-1; i++)
+            timer_ticks[i] = timer_ticks[i+1] - timer_ticks[i];
+
+        qsort(timer_ticks, TIMER_COUNT - 1, sizeof(timer_ticks[0]), compare_ulonglong);
+
+        ret = QueryPerformanceFrequency(&performance_frequency);
+        ok(ret, "QueryPerformanceFrequency failed\n");
+
+        /* median duration, converted to microseconds */
+        timer_duration = (int)(timer_ticks[(TIMER_COUNT - 1) / 2] * 1000000 / performance_frequency.QuadPart);
+    }
+}
+
+static void CALLBACK callback_count(HWND hwnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime)
+{
+    timer_fired();
 }

static DWORD exception;
 static void CALLBACK callback_exception(HWND hwnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime)
 {
-    count++;
+    timer_fired();
     RaiseException(exception, 0, 0, NULL);
 }

@@ -11583,7 +11630,6 @@ static DWORD WINAPI timer_thread_proc(LPVOID x)
 static void test_timers(void)
 {
     struct timer_info info;
-    DWORD start;
     DWORD id;
     MSG msg;

@@ -11609,44 +11655,37 @@ static void test_timers(void)

/* Check the minimum allowed timeout for a timer.  MSDN indicates that it should be 10.0 ms,
      * which occurs sometimes, but most testing on the VMs indicates a minimum timeout closer to
-     * 15.6 ms.  Since there is some measurement error between test runs we are allowing for
-     * ±9 counts (~4 ms) around the expected value.
+     * 15.6 ms.
      */
     count = 0;
     id = SetTimer(info.hWnd, TIMER_ID, 0, callback_count);
     ok(id != 0, "did not get id from SetTimer.\n");
     ok(id==TIMER_ID, "SetTimer timer ID different\n");
-    start = GetTickCount();
-    while (GetTickCount()-start < 1001 && GetMessageA(&msg, info.hWnd, 0, 0))
+    while (count < TIMER_COUNT && GetMessageA(&msg, info.hWnd, 0, 0))
         DispatchMessageA(&msg);
-    ok(abs(count-TIMER_COUNT_EXPECTED) < TIMER_COUNT_TOLERANCE /* xp */
-       || broken(abs(count-64) <= TIMER_COUNT_TOLERANCE) /* most common */
-       || broken(abs(count-43) <= TIMER_COUNT_TOLERANCE) /* w2k3, win8 */,
-       "did not get expected count for minimum timeout (%d != ~%d).\n",
-       count, TIMER_COUNT_EXPECTED);
+    ok(abs(timer_duration-TIMER_DURATION_EXPECTED) < TIMER_DURATION_TOLERANCE /* xp, win7 */
+       || broken(abs(timer_duration - TIMER_DURATION_ALT) < TIMER_DURATION_TOLERANCE) /* most common */,
+       "did not get expected median timeout (%d != ~%d).\n",
+       timer_duration, TIMER_DURATION_EXPECTED);
     ok(KillTimer(info.hWnd, id), "KillTimer failed\n");
     /* Perform the same check on SetSystemTimer (only available on w2k3 and older) */
     if (pSetSystemTimer)
     {
-        int syscount = 0;
-
         count = 0;
         id = pSetSystemTimer(info.hWnd, TIMER_ID, 0, callback_count);
         ok(id != 0, "did not get id from SetSystemTimer.\n");
         ok(id==TIMER_ID, "SetTimer timer ID different\n");
-        start = GetTickCount();
-        while (GetTickCount()-start < 1001 && GetMessageA(&msg, info.hWnd, 0, 0))
+        while (count < TIMER_COUNT && GetMessageA(&msg, info.hWnd, 0, 0))
         {
             if (msg.message == WM_SYSTIMER)
-                syscount++;
+                timer_fired();
+            ok(msg.message != WM_TIMER, "unexpected WM_TIMER\n");
             DispatchMessageA(&msg);
         }
-        ok(abs(syscount-TIMER_COUNT_EXPECTED) < TIMER_COUNT_TOLERANCE
-           || broken(abs(syscount-64) < TIMER_COUNT_TOLERANCE) /* most common */
-           || broken(syscount > 4000 && syscount < 12000) /* win2k3sp0 */,
-           "did not get expected count for minimum timeout (%d != ~%d).\n",
-           syscount, TIMER_COUNT_EXPECTED);
-        ok(count == 0, "did not get expected count for callback timeout (%d != 0).\n", count);
+        ok(abs(timer_duration-TIMER_DURATION_EXPECTED) < TIMER_DURATION_TOLERANCE
+           || broken(abs(timer_duration - TIMER_DURATION_ALT) < TIMER_DURATION_TOLERANCE) /* most common */,
+           "did not get expected median timeout (%d != ~%d).\n",
+           timer_duration, TIMER_DURATION_EXPECTED);
         ok(pKillSystemTimer(info.hWnd, id), "KillSystemTimer failed\n");
     }

@@ -11679,20 +11718,17 @@ static void test_timers_no_wnd(void)

/* Check the minimum allowed timeout for a timer.  MSDN indicates that it should be 10.0 ms,
      * which occurs sometimes, but most testing on the VMs indicates a minimum timeout closer to
-     * 15.6 ms.  Since there is some measurement error between test runs we are allowing for
-     * ±9 counts (~4 ms) around the expected value.
+     * 15.6 ms.
      */
     count = 0;
     id = SetTimer(NULL, 0, 0, callback_count);
     ok(id != 0, "did not get id from SetTimer.\n");
-    start = GetTickCount();
-    while (GetTickCount()-start < 1001 && GetMessageA(&msg, NULL, 0, 0))
+    while (count < TIMER_COUNT && GetMessageA(&msg, NULL, 0, 0))
         DispatchMessageA(&msg);
-    ok(abs(count-TIMER_COUNT_EXPECTED) < TIMER_COUNT_TOLERANCE /* xp */
-       || broken(abs(count-64) <= TIMER_COUNT_TOLERANCE) /* most common */
-       || broken(abs(count-43) <= TIMER_COUNT_TOLERANCE) /* w1064v1809 */,
-       "did not get expected count for minimum timeout (%d != ~%d).\n",
-       count, TIMER_COUNT_EXPECTED);
+    ok(abs(timer_duration-TIMER_DURATION_EXPECTED) < TIMER_DURATION_TOLERANCE /* xp */
+       || broken(abs(timer_duration - TIMER_DURATION_ALT) < TIMER_DURATION_TOLERANCE) /* most common */,
+       "did not get expected median timeout (%d != ~%d).\n",
+       timer_duration, TIMER_DURATION_EXPECTED);
     KillTimer(NULL, id);
     /* Note: SetSystemTimer doesn't support a NULL window, see test_timers */

[Esme Povirk (＠madewokherd)]

Seems like testbot didn't pick up this patch. I wonder if the bridge is broken.

[Esme Povirk (＠madewokherd)]

Or maybe the mailing list is slow.