Merge branch 'osx-clock'

Moves the thread into real-time scheduling class, as recommended in [1], it
fixes the separate test provided by @ygj6 [2] everywhere (github actions,
travis-ci, appveyor) under osx.

  [1]: https://developer.apple.com/library/archive/technotes/tn2169/_index.html
  [2]: dde1a6e4d0

Although even after this changes the following time-related tests failed
on travis-ci:
- no_events
- del_wait

But anyway I guess #940 can be closed, since this fixes the issue in common.

* osx-clock:
  test: Use THREAD_* wrappers in del_notify/del_wait
  test: move threads created with THREAD_START() to realtime scheduling class too
  test: put thread into real time scheduling class on osx for better latencies

Closes: #940
(cherry picked from commit a6f81aa45455c8afb69980f7026a0e706f4f9387)

CMakeLists.txt

@@ -440,6 +440,7 @@ endif()
 CHECK_INCLUDE_FILE(sys/uio.h EVENT__HAVE_SYS_UIO_H)
 CHECK_INCLUDE_FILES("sys/types.h;ifaddrs.h" EVENT__HAVE_IFADDRS_H)
 CHECK_INCLUDE_FILE(mach/mach_time.h EVENT__HAVE_MACH_MACH_TIME_H)
+CHECK_INCLUDE_FILE(mach/mach.h EVENT__HAVE_MACH_MACH_H)
 CHECK_INCLUDE_FILE(netinet/tcp.h EVENT__HAVE_NETINET_TCP_H)
 CHECK_INCLUDE_FILE(sys/wait.h EVENT__HAVE_SYS_WAIT_H)
 CHECK_INCLUDE_FILE(sys/resource.h EVENT__HAVE_SYS_RESOURCE_H)

configure.ac

@@ -222,6 +222,7 @@ AC_CHECK_HEADERS([ \
   fcntl.h \
   ifaddrs.h \
   mach/mach_time.h \
+  mach/mach.h \
   netdb.h \
   netinet/in.h \
   netinet/in6.h \

event-config.h.cmake

@@ -178,6 +178,9 @@
 /* Define to 1 if you have the <mach/mach_time.h> header file. */
 #cmakedefine EVENT__HAVE_MACH_MACH_TIME_H 1
 
+/* Define to 1 if you have the <mach/mach.h> header file. */
+#cmakedefine EVENT__HAVE_MACH_MACH_H 1
+
 /* Define to 1 if you have the <memory.h> header file. */
 #cmakedefine EVENT__HAVE_MEMORY_H 1
 

test/regress.c

@@ -31,10 +31,6 @@
 #include <windows.h>
 #endif
 
-#ifdef EVENT__HAVE_PTHREADS
-#include <pthread.h>
-#endif
-
 #include "event2/event-config.h"
 
 #include <sys/types.h>
@@ -73,6 +69,7 @@
 #include "time-internal.h"
 
 #include "regress.h"
+#include "regress_thread.h"
 
 #ifndef _WIN32
 #include "regress.gen.h"
@@ -979,7 +976,7 @@ test_fork(void)
 		evutil_closesocket(child_pair[1]);
 }
 
-#ifdef EVENT__HAVE_PTHREADS
+#ifdef EVTHREAD_USE_PTHREADS_IMPLEMENTED
 static void* del_wait_thread(void *arg)
 {
 	struct timeval tv_start, tv_end;
@@ -1007,14 +1004,14 @@ static void
 test_del_wait(void)
 {
 	struct event ev;
-	pthread_t thread;
+	THREAD_T thread;
 
 	setup_test("event_del will wait: ");
 
 	event_set(&ev, pair[1], EV_READ|EV_PERSIST, del_wait_cb, &ev);
 	event_add(&ev, NULL);
 
-	pthread_create(&thread, NULL, del_wait_thread, NULL);
+	THREAD_START(thread, del_wait_thread, NULL);
 
 	if (write(pair[0], TEST1, strlen(TEST1)+1) < 0) {
 		tt_fail_perror("write");
@@ -1033,7 +1030,7 @@ test_del_wait(void)
 		test_timeval_diff_eq(&tv_start, &tv_end, 270);
 	}
 
-	pthread_join(thread, NULL);
+	THREAD_JOIN(thread);
 
 	tt_int_op(test_ok, ==, 1);
 
@@ -3505,8 +3502,8 @@ struct testcase_t main_testcases[] = {
 #ifndef _WIN32
 	LEGACY(fork, TT_ISOLATED),
 #endif
-#ifdef EVENT__HAVE_PTHREADS
+
-	/** TODO: support win32 */
+#ifdef EVTHREAD_USE_PTHREADS_IMPLEMENTED
 	LEGACY(del_wait, TT_ISOLATED|TT_NEED_THREADS|TT_RETRIABLE),
 	LEGACY(del_notify, TT_ISOLATED|TT_NEED_THREADS),
 #endif

test/regress.h

@@ -139,6 +139,7 @@ SSL_CTX *get_ssl_ctx(void);
 void init_ssl(void);
 #endif
 
+void   thread_setup(pthread_t pthread);
 void * basic_test_setup(const struct testcase_t *testcase);
 int    basic_test_cleanup(const struct testcase_t *testcase, void *ptr);
 

test/regress_main.c

@@ -186,6 +186,52 @@ ignore_log_cb(int s, const char *msg)
 {
 }
 
+#if defined(__APPLE__)
+
+#ifdef EVENT__HAVE_MACH_MACH_H
+#include <mach/mach.h>
+#endif
+#ifdef EVENT__HAVE_MACH_MACH_TIME_H
+#include <mach/mach_time.h>
+#endif
+#include <pthread.h>
+
+/**
+ * Put into the real time scheduling class for better timers latency.
+ * https://developer.apple.com/library/archive/technotes/tn2169/_index.html#//apple_ref/doc/uid/DTS40013172-CH1-TNTAG6000
+ */
+void move_pthread_to_realtime_scheduling_class(pthread_t pthread)
+{
+	mach_timebase_info_data_t timebase_info;
+	mach_timebase_info(&timebase_info);
+
+	const uint64_t NANOS_PER_MSEC = 1000000ULL;
+	double clock2abs = ((double)timebase_info.denom / (double)timebase_info.numer) * NANOS_PER_MSEC;
+
+	thread_time_constraint_policy_data_t policy;
+	policy.period      = 0;
+	policy.computation = (uint32_t)(5 * clock2abs); // 5 ms of work
+	policy.constraint  = (uint32_t)(10 * clock2abs);
+	policy.preemptible = FALSE;
+
+	int kr = thread_policy_set(pthread_mach_thread_np(pthread_self()),
+		THREAD_TIME_CONSTRAINT_POLICY,
+		(thread_policy_t)&policy,
+		THREAD_TIME_CONSTRAINT_POLICY_COUNT);
+	if (kr != KERN_SUCCESS) {
+		mach_error("thread_policy_set:", kr);
+		exit(1);
+	}
+}
+
+void thread_setup(pthread_t pthread)
+{
+	move_pthread_to_realtime_scheduling_class(pthread);
+}
+#else
+void thread_setup(pthread_t pthread) {}
+#endif
+
 void *
 basic_test_setup(const struct testcase_t *testcase)
 {
@@ -193,6 +239,8 @@ basic_test_setup(const struct testcase_t *testcase)
 	evutil_socket_t spair[2] = { -1, -1 };
 	struct basic_test_data *data = NULL;
 
+	thread_setup(pthread_self());
+
 #ifndef _WIN32
 	if (testcase->flags & TT_ENABLE_IOCP_FLAG)
 		return (void*)TT_SKIP;

test/regress_thread.h

@@ -27,13 +27,17 @@
 #ifndef REGRESS_THREAD_H_INCLUDED_
 #define REGRESS_THREAD_H_INCLUDED_
 
+#include "regress.h"
+
 #ifdef EVENT__HAVE_PTHREADS
 #include <pthread.h>
 #define THREAD_T pthread_t
 #define THREAD_FN void *
 #define THREAD_RETURN() return (NULL)
-#define THREAD_START(threadvar, fn, arg) \
+#define THREAD_START(threadvar, fn, arg) do {          \
-	pthread_create(&(threadvar), NULL, fn, arg)
+	if (!pthread_create(&(threadvar), NULL, fn, arg))  \
+		thread_setup(threadvar);                       \
+} while (0)
 #define THREAD_JOIN(th) pthread_join(th, NULL)
 #else
 #define THREAD_T HANDLE
@@ -42,7 +46,7 @@
 #define THREAD_START(threadvar, fn, arg) do {		\
 	uintptr_t threadhandle = _beginthreadex(NULL,0,fn,(arg),0,NULL);  \
 	(threadvar) = (HANDLE) threadhandle;                              \
-	} while (0)
+} while (0)
 #define THREAD_JOIN(th) WaitForSingleObject(th, INFINITE)
 #endif