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authorErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
committerErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
commit84adefa331c4159d432d22840663c38f155cd4c1 (patch)
treebff9a9c66adda4df2106dfd0e5c053ab182a12bd /erts/emulator/sys/unix/sys_time.c
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The R13B03 release.OTP_R13B03
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diff --git a/erts/emulator/sys/unix/sys_time.c b/erts/emulator/sys/unix/sys_time.c
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+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2005-2009. All Rights Reserved.
+ *
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * %CopyrightEnd%
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+/* These need to be undef:ed to not break activation of
+ * micro level process accounting on /proc/self
+ */
+#ifdef _LARGEFILE_SOURCE
+# undef _LARGEFILE_SOURCE
+#endif
+#ifdef _FILE_OFFSET_BITS
+# undef _FILE_OFFSET_BITS
+#endif
+
+#include "sys.h"
+#include "global.h"
+
+#ifdef NO_SYSCONF
+# define TICKS_PER_SEC() HZ
+#else
+#define TICKS_PER_SEC() sysconf(_SC_CLK_TCK)
+#endif
+
+#ifdef HAVE_GETHRVTIME_PROCFS_IOCTL
+# include <unistd.h>
+# include <sys/types.h>
+# include <sys/stat.h>
+# include <sys/signal.h>
+# include <sys/fault.h>
+# include <sys/syscall.h>
+# include <sys/procfs.h>
+# include <fcntl.h>
+#endif
+
+/******************* Routines for time measurement *********************/
+
+int erts_ticks_per_sec = 0; /* Will be SYS_CLK_TCK in erl_unix_sys.h */
+int erts_ticks_per_sec_wrap = 0; /* Will be SYS_CLK_TCK_WRAP */
+static int ticks_bsr = 0; /* Shift wrapped tick value this much to the right */
+
+/*
+ * init timers, chose a tick length, and return it.
+ * Unix is priviliged when it comes to time, as erl_time_sup.c
+ * does almost everything. Other platforms have to
+ * emulate Unix in this sense.
+ */
+int sys_init_time(void)
+{
+ /*
+ * This (erts_ticks_per_sec) is only for times() (CLK_TCK),
+ * the resolution is always one millisecond..
+ */
+ if ((erts_ticks_per_sec = TICKS_PER_SEC()) < 0)
+ erl_exit(1, "Can't get clock ticks/sec\n");
+ if (erts_ticks_per_sec >= 1000) {
+ /* Workaround for beta linux kernels, need to be done in runtime
+ to make erlang run on both 2.4 and 2.5 kernels. In the future,
+ the kernel ticks might as
+ well be used as a high res timer instead, but that's for when the
+ majority uses kernels with HZ == 1024 */
+ ticks_bsr = 3;
+ } else {
+ ticks_bsr = 0;
+ }
+ erts_ticks_per_sec_wrap = (erts_ticks_per_sec >> ticks_bsr);
+ return SYS_CLOCK_RESOLUTION;
+}
+
+clock_t sys_times_wrap(void)
+{
+ SysTimes dummy;
+ clock_t result = (sys_times(&dummy) >> ticks_bsr);
+ return result;
+}
+
+
+
+
+#ifdef HAVE_GETHRVTIME_PROCFS_IOCTL
+
+int sys_start_hrvtime(void)
+{
+ long msacct = PR_MSACCT;
+ int fd;
+
+ if ( (fd = open("/proc/self", O_WRONLY)) == -1) {
+ return -1;
+ }
+ if (ioctl(fd, PIOCSET, &msacct) < 0) {
+ close(fd);
+ return -2;
+ }
+ close(fd);
+ return 0;
+}
+
+int sys_stop_hrvtime(void)
+{
+ long msacct = PR_MSACCT;
+ int fd;
+
+ if ( (fd = open("/proc/self", O_WRONLY)) == -1) {
+ return -1;
+ }
+ if (ioctl(fd, PIOCRESET, &msacct) < 0) {
+ close(fd);
+ return -2;
+ }
+ close(fd);
+ return 0;
+}
+
+#endif /* HAVE_GETHRVTIME_PROCFS_IOCTL */
+
+