Refine nstime_update().

Add missing #include <time.h>.  The critical time facilities appear to
have been transitively included via unistd.h and sys/time.h, but in
principle this omission was capable of having caused
clock_gettime(CLOCK_MONOTONIC, ...) to have been overlooked in favor of
gettimeofday(), which in turn could cause spurious non-monotonic time
updates.

Refactor nstime_get() out of nstime_update() and add configure tests for
all variants.

Add CLOCK_MONOTONIC_RAW support (Linux-specific) and
mach_absolute_time() support (OS X-specific).

Do not fall back to clock_gettime(CLOCK_REALTIME, ...).  This was a
fragile Linux-specific workaround, which we're unlikely to use at all
now that clock_gettime(CLOCK_MONOTONIC_RAW, ...) is supported, and if we
have no choice besides non-monotonic clocks, gettimeofday() is only
incrementally worse.

configure.ac

@@ -345,11 +345,11 @@ dnl
 dnl Define cpp macros in CPPFLAGS, rather than doing AC_DEFINE(macro), since the
 dnl definitions need to be seen before any headers are included, which is a pain
 dnl to make happen otherwise.
+CFLAGS="$CFLAGS"
 default_munmap="1"
 maps_coalesce="1"
 case "${host}" in
   *-*-darwin* | *-*-ios*)
-	CFLAGS="$CFLAGS"
 	abi="macho"
 	AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
 	RPATH=""
@@ -362,30 +362,26 @@ case "${host}" in
 	sbrk_deprecated="1"
 	;;
   *-*-freebsd*)
-	CFLAGS="$CFLAGS"
 	abi="elf"
 	AC_DEFINE([JEMALLOC_SYSCTL_VM_OVERCOMMIT], [ ])
 	AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
 	force_lazy_lock="1"
 	;;
   *-*-dragonfly*)
-	CFLAGS="$CFLAGS"
 	abi="elf"
 	AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
 	;;
   *-*-openbsd*)
-	CFLAGS="$CFLAGS"
 	abi="elf"
 	AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
 	force_tls="0"
 	;;
   *-*-bitrig*)
-	CFLAGS="$CFLAGS"
 	abi="elf"
 	AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
 	;;
   *-*-linux*)
-	CFLAGS="$CFLAGS"
+	dnl secure_getenv() is exposed by _GNU_SOURCE.
 	CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE"
 	abi="elf"
 	AC_DEFINE([JEMALLOC_HAS_ALLOCA_H])
@@ -404,13 +400,12 @@ case "${host}" in
 #error aout
 #endif
 ]])],
-                          [CFLAGS="$CFLAGS"; abi="elf"],
+                          [abi="elf"],
                           [abi="aout"])
 	AC_MSG_RESULT([$abi])
 	AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
 	;;
   *-*-solaris2*)
-	CFLAGS="$CFLAGS"
 	abi="elf"
 	AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
 	RPATH='-Wl,-R,$(1)'
@@ -1309,6 +1304,44 @@ if test "x$je_cv_cray_prgenv_wrapper" = "xyes" ; then
   fi
 fi
 
+dnl check for CLOCK_MONOTONIC_RAW (Linux-specific).
+JE_COMPILABLE([clock_gettime(CLOCK_MONOTONIC_RAW, ...)], [
+#include <time.h>
+], [
+	struct timespec ts;
+
+	clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
+], [je_cv_clock_monotonic_raw])
+if test "x${je_cv_clock_monotonic_raw}" = "xyes" ; then
+  AC_DEFINE([JEMALLOC_HAVE_CLOCK_MONOTONIC_RAW])
+fi
+
+dnl check for CLOCK_MONOTONIC.
+JE_COMPILABLE([clock_gettime(CLOCK_MONOTONIC, ...)], [
+#include <unistd.h>
+#include <time.h>
+], [
+	struct timespec ts;
+
+	clock_gettime(CLOCK_MONOTONIC, &ts);
+#if !defined(_POSIX_MONOTONIC_CLOCK) || _POSIX_MONOTONIC_CLOCK < 0
+#  error _POSIX_MONOTONIC_CLOCK missing/invalid
+#endif
+], [je_cv_clock_monotonic])
+if test "x${je_cv_clock_monotonic}" = "xyes" ; then
+  AC_DEFINE([JEMALLOC_HAVE_CLOCK_MONOTONIC])
+fi
+
+dnl Check for mach_absolute_time().
+JE_COMPILABLE([mach_absolute_time()], [
+#include <mach/mach_time.h>
+], [
+	mach_absolute_time();
+], [je_cv_mach_absolute_time])
+if test "x${je_cv_mach_absolute_time}" = "xyes" ; then
+  AC_DEFINE([JEMALLOC_HAVE_MACH_ABSOLUTE_TIME])
+fi
+
 dnl Check if the GNU-specific secure_getenv function exists.
 AC_CHECK_FUNC([secure_getenv],
               [have_secure_getenv="1"],

include/jemalloc/internal/jemalloc_internal_decls.h

@@ -19,6 +19,10 @@
 #  include <pthread.h>
 #  include <errno.h>
 #  include <sys/time.h>
+#  include <time.h>
+#  ifdef JEMALLOC_HAVE_MACH_ABSOLUTE_TIME
+#    include <mach/mach_time.h>
+#  endif
 #endif
 #include <sys/types.h>
 

include/jemalloc/internal/jemalloc_internal_defs.h.in

@@ -76,6 +76,21 @@
  */
 #undef JEMALLOC_HAVE_ISSETUGID
 
+/*
+ * Defined if clock_gettime(CLOCK_MONOTONIC_RAW, ...) is available.
+ */
+#undef JEMALLOC_HAVE_CLOCK_MONOTONIC_RAW
+
+/*
+ * Defined if clock_gettime(CLOCK_MONOTONIC, ...) is available.
+ */
+#undef JEMALLOC_HAVE_CLOCK_MONOTONIC
+
+/*
+ * Defined if mach_absolute_time() is available.
+ */
+#undef JEMALLOC_HAVE_MACH_ABSOLUTE_TIME
+
 /*
  * Defined if _malloc_thread_cleanup() exists.  At least in the case of
  * FreeBSD, pthread_key_create() allocates, which if used during malloc

include/jemalloc/internal/nstime.h

@@ -1,9 +1,6 @@
 /******************************************************************************/
 #ifdef JEMALLOC_H_TYPES
 
-#define	JEMALLOC_CLOCK_GETTIME defined(_POSIX_MONOTONIC_CLOCK) \
-    && _POSIX_MONOTONIC_CLOCK >= 0
-
 typedef struct nstime_s nstime_t;
 
 /* Maximum supported number of seconds (~584 years). */

src/nstime.c

@@ -97,6 +97,54 @@ nstime_divide(const nstime_t *time, const nstime_t *divisor)
 	return (time->ns / divisor->ns);
 }
 
+#ifdef _WIN32
+static void
+nstime_get(nstime_t *time)
+{
+	FILETIME ft;
+	uint64_t ticks_100ns;
+
+	GetSystemTimeAsFileTime(&ft);
+	ticks_100ns = (((uint64_t)ft.dwHighDateTime) << 32) | ft.dwLowDateTime;
+
+	nstime_init(time, ticks_100ns * 100);
+}
+#elif JEMALLOC_HAVE_CLOCK_MONOTONIC_RAW
+static void
+nstime_get(nstime_t *time)
+{
+	struct timespec ts;
+
+	clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
+	nstime_init2(time, ts.tv_sec, ts.tv_nsec);
+}
+#elif JEMALLOC_HAVE_CLOCK_MONOTONIC
+static void
+nstime_get(nstime_t *time)
+{
+	struct timespec ts;
+
+	clock_gettime(CLOCK_MONOTONIC, &ts);
+	nstime_init2(time, ts.tv_sec, ts.tv_nsec);
+}
+#elif JEMALLOC_HAVE_MACH_ABSOLUTE_TIME
+static void
+nstime_get(nstime_t *time)
+{
+
+	nstime_init(time, mach_absolute_time());
+}
+#else
+static void
+nstime_get(nstime_t *time)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+	nstime_init2(time, tv.tv_sec, tv.tv_usec * 1000);
+}
+#endif
+
 #ifdef JEMALLOC_JET
 #undef nstime_update
 #define	nstime_update JEMALLOC_N(n_nstime_update)
@@ -107,33 +155,7 @@ nstime_update(nstime_t *time)
 	nstime_t old_time;
 
 	nstime_copy(&old_time, time);
-
+	nstime_get(time);
-#ifdef _WIN32
-	{
-		FILETIME ft;
-		uint64_t ticks;
-		GetSystemTimeAsFileTime(&ft);
-		ticks = (((uint64_t)ft.dwHighDateTime) << 32) |
-		    ft.dwLowDateTime;
-		time->ns = ticks * 100;
-	}
-#elif JEMALLOC_CLOCK_GETTIME
-	{
-		struct timespec ts;
-
-		if (sysconf(_SC_MONOTONIC_CLOCK) > 0)
-			clock_gettime(CLOCK_MONOTONIC, &ts);
-		else
-			clock_gettime(CLOCK_REALTIME, &ts);
-		time->ns = ts.tv_sec * BILLION + ts.tv_nsec;
-	}
-#else
-	{
-		struct timeval tv;
-		gettimeofday(&tv, NULL);
-		time->ns = tv.tv_sec * BILLION + tv.tv_usec * 1000;
-	}
-#endif
 
 	/* Handle non-monotonic clocks. */
 	if (unlikely(nstime_compare(&old_time, time) > 0)) {