core: remove use of clock_gettime(3)

The portability of clock_gettime(3) on Mac OS / OS X
is... complicated.  Per
Homebrew/homebrew-core#6551 and
ofiwg#2508, remove the use of
clock_gettime(3) from the core of libfabric.  clock_gettime(3) is
still used in some providers that do not compile on OS X / MacOS, but
that's ok).

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>

Makefile.am

@@ -57,10 +57,6 @@ common_srcs = \
 	prov/util/src/util_mr.c
 
 if MACOS
-if !HAVE_CLOCK_GETTIME
-common_srcs += src/osx/osd.c
-endif
-
 common_srcs += src/unix/osd.c
 common_srcs += include/osx/osd.h
 common_srcs += include/unix/osd.h

configure.ac

@@ -125,24 +125,11 @@ fi
 AC_DEFINE_UNQUOTED([PT_LOCK_SPIN], [$have_spinlock],
 	[Define to 1 if pthread_spin_init is available.])
 
-have_clock_gettime=0
-
 AC_CHECK_FUNCS([epoll_create])
 if test "$ac_cv_func_epoll_create" = yes; then
   AC_DEFINE([HAVE_EPOLL], [1], [Define if you have epoll support.])
 fi
 
-AC_SEARCH_LIBS([clock_gettime],[rt],
-		[have_clock_gettime=1],
-		[AC_CHECK_FUNCS([host_get_clock_service],
-			[],
-			[AC_MSG_ERROR([clock_gettime or host_get_clock_service
-			 not found.])])])
-
-AC_DEFINE_UNQUOTED(HAVE_CLOCK_GETTIME, [$have_clock_gettime],
-		   [Define to 1 if clock_gettime is available.])
-AM_CONDITIONAL(HAVE_CLOCK_GETTIME, [test $have_clock_gettime -eq 1])
-
 dnl Check for gcc atomic intrinsics
 AC_MSG_CHECKING(compiler support for c11 atomics)
 AC_TRY_LINK([#include <stdatomic.h>],

include/fi_lock.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2013-2014 Intel Corporation. All rights reserved.
+ * Copyright (c) 2016 Cisco Systems, Inc. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -47,7 +48,8 @@ extern "C" {
 #endif
 
 
-int fi_wait_cond(pthread_cond_t *cond, pthread_mutex_t *mut, int timeout);
+/* timeout is expressed in miliseconds */
+int fi_wait_cond(pthread_cond_t *cond, pthread_mutex_t *mut, int timeout_ms);
 
 
 #if PT_LOCK_SPIN == 1

include/osx/osd.h

@@ -62,19 +62,6 @@
 extern "C" {
 #endif
 
-/* macOS Sierra added clock_gettime to libc. This implementation should only
- * take effect if it is not available.
- */
-#if !HAVE_CLOCK_GETTIME
-
-#define CLOCK_REALTIME CALENDAR_CLOCK
-#define CLOCK_MONOTONIC SYSTEM_CLOCK
-
-typedef int clockid_t;
-int clock_gettime(clockid_t clk_id, struct timespec *tp);
-
-#endif
-
 static inline int ofi_shm_remap(struct util_shm *shm, size_t newsize, void **mapped)
 {
 	return -1;

src/unix/osd.c

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2013-2016 Intel Corporation. All rights reserved.
+ * Copyright (c) 2016 Cisco Systems, Inc.  All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -42,6 +43,7 @@
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 
 #include "fi.h"
 #include "fi_osd.h"
@@ -65,16 +67,29 @@ int fi_fd_nonblock(int fd)
 	return 0;
 }
 
-int fi_wait_cond(pthread_cond_t *cond, pthread_mutex_t *mut, int timeout)
+/* timeout is expressed in miliseconds */
+int fi_wait_cond(pthread_cond_t *cond, pthread_mutex_t *mut, int timeout_ms)
 {
+	int ret;
+	struct timeval tv;
+	uint64_t t;
 	struct timespec ts;
 
-	if (timeout < 0)
+	if (timeout_ms < 0)
 		return pthread_cond_wait(cond, mut);
 
-	clock_gettime(CLOCK_REALTIME, &ts);
-	ts.tv_sec += timeout / 1000;
-	ts.tv_nsec += (timeout % 1000) * 1000000;
+	ret = gettimeofday(&tv, NULL);
+	if (ret < 0)
+		return ret;
+
+	/* Set t to now, expressed in microseconds */
+	t = (tv.tv_sec + (timeout_ms / 1000)) * 1000000;
+	t += (timeout_ms % 1000) * 1000;
+	t += tv.tv_usec;
+
+	/* Convert t to a struct timespec */
+	ts.tv_sec = t / 1000000;
+	ts.tv_nsec = t % 1000000;
 	return pthread_cond_timedwait(cond, mut, &ts);
 }
 

util/pingpong.c

@@ -160,6 +160,11 @@ int pp_debug;
 	})
 #endif
 
+struct pp_time {
+	time_t sec;
+	long nsec;
+};
+
 struct ct_pingpong {
 	struct fi_info *fi_pep, *fi, *hints;
 	struct fid_fabric *fabric;
@@ -182,7 +187,7 @@ struct ct_pingpong {
 	size_t buf_size, tx_size, rx_size;
 
 	int timeout;
-	struct timespec start, end;
+	struct pp_time start, end;
 
 	struct fi_av_attr av_attr;
 	struct fi_eq_attr eq_attr;
@@ -205,20 +210,52 @@ static const int integ_alphabet_length =
 /*******************************************************************************
  *                                  Compatibility methods
  ******************************************************************************/
-#if defined(__APPLE__) && !HAVE_CLOCK_GETTIME
-int clock_gettime(clockid_t clk_id, struct timespec *tp)
+
+int pp_clock_gettime(struct pp_time *ofit)
 {
+#if defined(__APPLE__)
+	/* clock_gettime(3) portability on OS X / Mac OS X is... complicated:
+	 *
+	 * 1. OS X 10.11 (El Capitan) and below do not have
+	 *    clock_gettime(3).
+	 * 2. MacOS 10.12 (Sierra) and above has clock_gettime(3).
+	 * 3. XCode 8.x allows you to build 10.12 applications on
+	 *    10.11 by setting the env var SDKROOT to point to the
+	 *    10.12 root. On 10.11, the SDK libraries contain a weak
+	 *    symbol for clock_gettime(3) (and some other POSIX
+	 *    functions).  Meaning:
+	 *    1. If you run the resulting executable on 10.11, you get
+	 *       a linker error because there is no strong symbol for
+	 *       clock_gettime behind the weak symbol.
+	 *    2. If you run the resulting executable on 10.12, it
+	 *    works fine.
+	 *
+	 * We *could* have some fairly complicated configury on OS X /
+	 * MacOS, but why bother?  Libfabric is built on OS X / MacOS
+	 * mainly for testing, not high performance -- meaning that
+	 * using gettimeofday(3) is sufficient for timing purposes.
+	 */
 	int retval;
 	struct timeval tv;
 
 	retval = gettimeofday(&tv, NULL);
 
-	tp->tv_sec = tv.tv_sec;
-	tp->tv_nsec = tv.tv_usec * 1000;
+	ofit->sec = tv.tv_sec;
+	ofit->nsec = tv.tv_usec * 1000;
+
+	return retval;
+#else
+	int retval;
+	struct timespec ts;
+
+	retval = clock_gettime(CLOCK_MONOTONIC, &ts);
+
+	ofit->sec = ts.tv_sec;
+	ofit->nsec = ts.tv_nsec;
 
 	return retval;
-}
 #endif
+}
 
 /*******************************************************************************
  *                                         Utils
@@ -804,12 +841,12 @@ static inline void pp_start(struct ct_pingpong *ct)
 {
 	PP_DEBUG("Starting test chrono\n");
 	ct->opts.options |= PP_OPT_ACTIVE;
-	clock_gettime(CLOCK_MONOTONIC, &(ct->start));
+	pp_clock_gettime(&(ct->start));
 }
 
 static inline void pp_stop(struct ct_pingpong *ct)
 {
-	clock_gettime(CLOCK_MONOTONIC, &(ct->end));
+	pp_clock_gettime(&(ct->end));
 	ct->opts.options &= ~PP_OPT_ACTIVE;
 	PP_DEBUG("Stopped test chrono\n");
 }
@@ -1015,18 +1052,18 @@ char *cnt_str(char *str, size_t size, uint64_t cnt)
 	return str;
 }
 
-int64_t get_elapsed(const struct timespec *b, const struct timespec *a,
+int64_t get_elapsed(const struct pp_time *b, const struct pp_time *a,
 		    enum precision p)
 {
 	int64_t elapsed;
 
-	elapsed = difftime(a->tv_sec, b->tv_sec) * 1000 * 1000 * 1000;
-	elapsed += a->tv_nsec - b->tv_nsec;
+	elapsed = difftime(a->sec, b->sec) * 1000 * 1000 * 1000;
+	elapsed += a->nsec - b->nsec;
 	return elapsed / p;
 }
 
 void show_perf(char *name, int tsize, int sent, int acked,
-	       struct timespec *start, struct timespec *end, int xfers_per_iter)
+	       struct pp_time *start, struct pp_time *end, int xfers_per_iter)
 {
 	static int header = 1;
 	char str[PP_STR_LEN];
@@ -1097,17 +1134,17 @@ static int pp_get_cq_comp(struct fid_cq *cq, uint64_t *cur, uint64_t total,
 			  int timeout)
 {
 	struct fi_cq_err_entry comp;
-	struct timespec a = {0}, b = {0};
+	struct pp_time a = {0}, b = {0};
 	int ret = 0;
 
 	if (timeout >= 0)
-		clock_gettime(CLOCK_MONOTONIC, &a);
+		pp_clock_gettime(&a);
 
 	while (total - *cur > 0) {
 		ret = fi_cq_read(cq, &comp, 1);
 		if (ret > 0) {
 			if (timeout >= 0)
-				clock_gettime(CLOCK_MONOTONIC, &a);
+				pp_clock_gettime(&a);
 
 			(*cur)++;
 		} else if (ret < 0 && ret != -FI_EAGAIN) {
@@ -1120,8 +1157,8 @@ static int pp_get_cq_comp(struct fid_cq *cq, uint64_t *cur, uint64_t total,
 
 			return ret;
 		} else if (timeout >= 0) {
-			clock_gettime(CLOCK_MONOTONIC, &b);
-			if ((b.tv_sec - a.tv_sec) > timeout) {
+			pp_clock_gettime(&b);
+			if ((b.sec - a.sec) > timeout) {
 				fprintf(stderr, "%ds timeout expired\n",
 					timeout);
 				return -FI_ENODATA;