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authorRickard Green <[email protected]>2015-03-22 20:20:28 +0100
committerRickard Green <[email protected]>2015-03-23 14:06:31 +0100
commitd07319f790eb38c867bd04a23de674e2393825ff (patch)
tree78237385072b7c478ec01cbd957941b2c1fc8084 /erts/emulator/sys/common
parent50713b7d6179477d6018e6a9ca5610617e3de1fe (diff)
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Better support for poor os monotonic sources
Diffstat (limited to 'erts/emulator/sys/common')
-rw-r--r--erts/emulator/sys/common/erl_os_monotonic_time_extender.c88
-rw-r--r--erts/emulator/sys/common/erl_os_monotonic_time_extender.h65
2 files changed, 153 insertions, 0 deletions
diff --git a/erts/emulator/sys/common/erl_os_monotonic_time_extender.c b/erts/emulator/sys/common/erl_os_monotonic_time_extender.c
new file mode 100644
index 0000000000..f3633b7267
--- /dev/null
+++ b/erts/emulator/sys/common/erl_os_monotonic_time_extender.c
@@ -0,0 +1,88 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2015. 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
+#include "erl_os_monotonic_time_extender.h"
+
+#ifdef USE_THREADS
+
+static void *os_monotonic_time_extender(void *vstatep)
+{
+ ErtsOsMonotonicTimeExtendState *state = (ErtsOsMonotonicTimeExtendState *) vstatep;
+ long sleep_time = state->check_interval*1000;
+ Uint32 (*raw_os_mtime)(void) = state->raw_os_monotonic_time;
+ Uint32 last_msb = 0;
+
+ while (1) {
+ Uint32 msb = (*raw_os_mtime)() & (((Uint32) 1) << 31);
+
+ if (msb != last_msb) {
+ int ix = ((int) (last_msb >> 31)) & 1;
+ Uint32 xtnd = (Uint32) erts_atomic32_read_nob(&state->extend[ix]);
+ erts_atomic32_set_nob(&state->extend[ix], (erts_aint32_t) (xtnd + 1));
+ last_msb = msb;
+ }
+ erts_milli_sleep(sleep_time);
+ }
+
+ erl_exit(ERTS_ABORT_EXIT, "os_monotonic_time_extender thread terminating");
+ return NULL;
+}
+
+static erts_tid_t os_monotonic_extender_tid;
+#endif
+
+void
+erts_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep,
+ Uint32 (*raw_os_monotonic_time)(void),
+ int check_seconds)
+{
+#ifdef USE_THREADS
+ statep->raw_os_monotonic_time = raw_os_monotonic_time;
+ erts_atomic32_init_nob(&statep->extend[0], (erts_aint32_t) 0);
+ erts_atomic32_init_nob(&statep->extend[1], (erts_aint32_t) 0);
+ statep->check_interval = check_seconds;
+
+#else
+ statep->extend[0] = (Uint32) 0;
+ statep->extend[1] = (Uint32) 0;
+ statep->last_msb = (ErtsMonotonicTime) 0;
+#endif
+}
+
+void
+erts_late_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep)
+{
+#ifdef USE_THREADS
+ erts_thr_opts_t thr_opts = ERTS_THR_OPTS_DEFAULT_INITER;
+ thr_opts.detached = 1;
+ thr_opts.suggested_stack_size = 4;
+
+#if 0
+ thr_opts.name = "os_monotonic_time_extender";
+#endif
+
+ erts_thr_create(&os_monotonic_extender_tid,
+ os_monotonic_time_extender,
+ (void*) statep,
+ &thr_opts);
+#endif
+}
diff --git a/erts/emulator/sys/common/erl_os_monotonic_time_extender.h b/erts/emulator/sys/common/erl_os_monotonic_time_extender.h
new file mode 100644
index 0000000000..0f9e7c86ae
--- /dev/null
+++ b/erts/emulator/sys/common/erl_os_monotonic_time_extender.h
@@ -0,0 +1,65 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2015. 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%
+ */
+
+#ifndef ERL_OS_MONOTONIC_TIME_EXTENDER_H__
+#define ERL_OS_MONOTONIC_TIME_EXTENDER_H__
+
+#include "sys.h"
+#include "erl_threads.h"
+
+typedef struct {
+#ifdef USE_THREADS
+ Uint32 (*raw_os_monotonic_time)(void);
+ erts_atomic32_t extend[2];
+ int check_interval;
+#else
+ Uint32 extend[2];
+ ErtsMonotonicTime last_msb;
+#endif
+} ErtsOsMonotonicTimeExtendState;
+
+#ifdef USE_THREADS
+# define ERTS_CHK_EXTEND_OS_MONOTONIC_TIME(S, RT) ((void) 1)
+# define ERTS_EXTEND_OS_MONOTONIC_TIME(S, RT) \
+ ((((ErtsMonotonicTime) \
+ erts_atomic32_read_nob(&((S)->extend[((int) ((RT) >> 31)) & 1]))) \
+ << 32) \
+ + (RT))
+#else
+# define ERTS_CHK_EXTEND_OS_MONOTONIC_TIME(S, RT) \
+ do { \
+ Uint32 msb__ = (RT) & (((Uint32) 1) << 31); \
+ if (msb__ != (S)->last_msb) { \
+ int ix__ = ((int) ((S)->last_msb >> 31)) & 1; \
+ (S)->extend[ix__]++; \
+ (S)->last_msb = msb; \
+ } \
+ } while (0)
+# define ERTS_EXTEND_OS_MONOTONIC_TIME(S, RT) \
+ ((((ErtsMonotonicTime) (S)->extend[((int) ((RT) >> 31)) & 1]) << 32) + (RT))
+#endif
+
+void
+erts_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep,
+ Uint32 (*raw_os_monotonic_time)(void),
+ int check_seconds);
+void
+erts_late_init_os_monotonic_time_extender(ErtsOsMonotonicTimeExtendState *statep);
+
+#endif