erts: Add microstate accounting

Microstate accounting is a way to track which state the
different threads within ERTS are in. The main usage area
is to pin point performance bottlenecks by checking which
states the threads are in and then from there figuring out
why and where to optimize.

Since checking whether microstate accounting is on or off is
relatively expensive if done in a short loop only a few of the
states are enabled by default and more states can be enabled
through configure.

I've done some benchmarking and the overhead with it turned off
is not noticible and with it on it is a fraction of a percent.
If you enable the extra states, depending on the benchmark,
the ovehead when turned off is about 1% and when turned on
somewhere inbetween 5-15%.

OTP-12345

1 files changed, 409 insertions, 0 deletions

diff --git a/erts/emulator/beam/erl_msacc.h b/erts/emulator/beam/erl_msacc.h
new file mode 100644
index 0000000000..de72fe9597
--- /dev/null
+++ b/erts/emulator/beam/erl_msacc.h
@@ -0,0 +1,409 @@
+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2014-2015. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * %CopyrightEnd%
+ */
+
+#ifndef ERL_MSACC_H__
+#define ERL_MSACC_H__
+
+/* Can be enabled/disabled via configure */
+#if ERTS_ENABLE_MSACC == 2
+#define ERTS_MSACC_EXTENDED_STATES 1
+#endif
+
+/* Uncomment this to also count the number of
+   transitions to a state. This will add a count
+   to the counter map. */
+/* #define ERTS_MSACC_STATE_COUNTERS 1 */
+
+/* Uncomment this to make msacc to always be on,
+   this reduces overhead a little bit when profiling */
+/* #define ERTS_MSACC_ALWAYS_ON 1 */
+
+#define ERTS_MSACC_DISABLE 0
+#define ERTS_MSACC_ENABLE  1
+#define ERTS_MSACC_RESET   2
+#define ERTS_MSACC_GATHER  3
+
+/*
+ * When adding a new state, you have to:
+ * * Add it here
+ * * Increment ERTS_MSACC_STATE_COUNT
+ * * Add string value to erts_msacc_states
+ * * Have to be in alphabetical order!
+ * * Only add states to the non-extended section after
+ *   careful benchmarking to make sure the overhead
+ *   when disabled is minimal.
+ */
+
+#ifndef ERTS_MSACC_EXTENDED_STATES
+#define ERTS_MSACC_STATE_AUX       0
+#define ERTS_MSACC_STATE_CHECK_IO  1
+#define ERTS_MSACC_STATE_EMULATOR  2
+#define ERTS_MSACC_STATE_GC        3
+#define ERTS_MSACC_STATE_OTHER     4
+#define ERTS_MSACC_STATE_PORT      5
+#define ERTS_MSACC_STATE_SLEEP     6
+
+#define ERTS_MSACC_STATE_COUNT 7
+
+#if ERTS_MSACC_STATE_STRINGS && ERTS_ENABLE_MSACC
+static char *erts_msacc_states[] = {
+    "aux",
+    "check_io",
+    "emulator",
+    "gc",
+    "other",
+    "port",
+    "sleep"
+};
+#endif
+
+#else
+
+#define ERTS_MSACC_STATE_ALLOC     0
+#define ERTS_MSACC_STATE_AUX       1
+#define ERTS_MSACC_STATE_BIF       2
+#define ERTS_MSACC_STATE_BUSY_WAIT 3
+#define ERTS_MSACC_STATE_CHECK_IO  4
+#define ERTS_MSACC_STATE_EMULATOR  5
+#define ERTS_MSACC_STATE_ETS       6
+#define ERTS_MSACC_STATE_GC        7
+#define ERTS_MSACC_STATE_GC_FULL   8
+#define ERTS_MSACC_STATE_NIF       9
+#define ERTS_MSACC_STATE_OTHER     10
+#define ERTS_MSACC_STATE_PORT      11
+#define ERTS_MSACC_STATE_SEND      12
+#define ERTS_MSACC_STATE_SLEEP     13
+#define ERTS_MSACC_STATE_TIMERS    14
+
+#define ERTS_MSACC_STATE_COUNT 15
+
+#if ERTS_MSACC_STATE_STRINGS
+static char *erts_msacc_states[] = {
+    "alloc",
+    "aux",
+    "bif",
+    "busy_wait",
+    "check_io",
+    "emulator",
+    "ets",
+    "gc",
+    "gc_full",
+    "nif",
+    "other",
+    "port",
+    "send",
+    "sleep",
+    "timers"
+};
+#endif
+
+#endif
+
+typedef struct erl_msacc_t_ ErtsMsAcc;
+
+struct erl_msacc_t_ {
+
+    /* the the values below are protected by mtx iff unmanaged = 1 */
+    ErtsSysHrTime perf_counter;
+    ErtsSysHrTime perf_counters[ERTS_MSACC_STATE_COUNT];
+#ifdef ERTS_MSACC_STATE_COUNTERS
+    Uint64 state_counters[ERTS_MSACC_STATE_COUNT];
+#endif
+    Uint state;
+
+    /* protected by msacc_mutex in erl_msacc.c, and should be constant */
+    int unmanaged;
+    erts_mtx_t mtx;
+    ErtsMsAcc *next;
+    erts_tid_t tid;
+    Eterm id;
+    char *type;
+};
+
+#if ERTS_ENABLE_MSACC
+
+#define ERTS_MSACC_INLINE ERTS_GLB_INLINE
+
+#ifdef USE_THREADS
+extern erts_tsd_key_t erts_msacc_key;
+#else
+extern ErtsMsAcc *erts_msacc;
+#endif
+
+#ifdef ERTS_MSACC_ALWAYS_ON
+#define erts_msacc_enabled 1
+#else
+extern int erts_msacc_enabled;
+#endif
+
+#ifdef USE_THREADS
+#define ERTS_MSACC_TSD_GET() erts_tsd_get(erts_msacc_key)
+#define ERTS_MSACC_TSD_SET(tsd) erts_tsd_set(erts_msacc_key,tsd)
+#else
+#define ERTS_MSACC_TSD_GET() erts_msacc
+#define ERTS_MSACC_TSD_SET(tsd) erts_msacc = tsd
+#endif
+
+void erts_msacc_early_init(void);
+void erts_msacc_init(void);
+void erts_msacc_init_thread(char *type, int id, int liberty);
+
+/* The defines below are used to instrument the vm code
+ * with different state changes. There are two variants
+ * of each define. One that has a cached ErtsMsAcc *
+ * that it can use, and one that does not.
+ * The cached values are necessary to have in order to get
+ * low enough overhead when running without msacc enabled.
+ *
+ * The two most common patterns to use the function with are:
+ *
+ *   ERTS_MSACC_PUSH_AND_SET_STATE(ERTS_MSACC_STATE_NEWSTATE);
+ *     ... call other function in new state ...
+ *   ERTS_MSACC_POP_STATE();
+ *
+ * Note that the erts_msacc_push* function declare new variables, so
+ * to conform with C89 we have to call it in the beginning of a function.
+ * We might not want to change state it the beginning though, so we use this:
+ *
+ *   ERTS_MSACC_PUSH_STATE();
+ *     ... some other code ...
+ *   ERTS_MSACC_SET_STATE_CACHED(ERTS_MSACC_STATE_NEWSTATE);
+ *     ... call other function in new state ...
+ *   ERTS_MSACC_POP_STATE();
+ *
+ * Notice that we used the cached version of set_state as push_state already
+ * read the erts_msacc_enabled to the cache.
+ *
+ * Most macros also have other variants with the suffix _m which means that
+ * they are known to only be called in managed threads, or with the _x suffix
+ * which means that it should only be used in an emulator compiled with
+ * extended states.
+ *
+ * Here is a listing of the entire api:
+ *
+ *  void ERTS_MSACC_DECLARE_CACHE()
+ *  void ERTS_MSACC_UPDATE_CACHE()
+ *  void ERTS_MSACC_IS_ENABLED()
+ *  void ERTS_MSACC_IS_ENABLED_CACHED()
+ *
+ *  void ERTS_MSACC_PUSH_STATE()
+ *  void ERTS_MSACC_SET_STATE(int state)
+ *  void ERTS_MSACC_PUSH_AND_SET_STATE(int state)
+ *
+ *  void ERTS_MSACC_PUSH_STATE_CACHED()
+ *  void ERTS_MSACC_SET_STATE_CACHED(int state)
+ *  void ERTS_MSACC_PUSH_AND_SET_STATE_CACHED(int state)
+ *  void ERTS_MSACC_POP_STATE()
+ *
+ *  void ERTS_MSACC_PUSH_STATE_M()
+ *  void ERTS_MSACC_PUSH_STATE_CACHED_M()
+ *  void ERTS_MSACC_SET_STATE_CACHED_M(int state)
+ *  void ERTS_MSACC_SET_STATE_M(int state)
+ *  void ERTS_MSACC_POP_STATE_M()
+ *  void ERTS_MSACC_PUSH_AND_SET_STATE_M(int state)
+ *
+ *  Most functions are also available with an _x suffix that are only enabled
+ *  when using the extra states. If they are not, just add them to the end
+ *  of this file.
+ */
+
+/* cache handling functions */
+#define ERTS_MSACC_IS_ENABLED() ERTS_UNLIKELY(erts_msacc_enabled)
+#define ERTS_MSACC_DECLARE_CACHE()                                      \
+    ErtsMsAcc *ERTS_MSACC_UPDATE_CACHE();                                 \
+    ERTS_DECLARE_DUMMY(Uint __erts_msacc_state) = ERTS_MSACC_STATE_OTHER
+#define ERTS_MSACC_IS_ENABLED_CACHED() ERTS_UNLIKELY(__erts_msacc_cache != NULL)
+#define ERTS_MSACC_UPDATE_CACHE()                                       \
+    __erts_msacc_cache = erts_msacc_enabled ? ERTS_MSACC_TSD_GET() : NULL
+
+
+/* The defines below implicitly declare and load a new cache */
+#define ERTS_MSACC_PUSH_STATE()                           \
+    ERTS_MSACC_DECLARE_CACHE();                           \
+    ERTS_MSACC_PUSH_STATE_CACHED()
+#define ERTS_MSACC_SET_STATE(state)                                     \
+    ERTS_MSACC_DECLARE_CACHE();                                         \
+    ERTS_MSACC_SET_STATE_CACHED(state)
+#define ERTS_MSACC_PUSH_AND_SET_STATE(state)                    \
+    ERTS_MSACC_PUSH_STATE(); ERTS_MSACC_SET_STATE_CACHED(state)
+
+/* The defines below need an already declared cache to work */
+#define ERTS_MSACC_PUSH_STATE_CACHED()                                  \
+    __erts_msacc_state = ERTS_MSACC_IS_ENABLED_CACHED() ?               \
+        erts_msacc_get_state_um__(__erts_msacc_cache) : ERTS_MSACC_STATE_OTHER
+#define ERTS_MSACC_SET_STATE_CACHED(state) \
+    if (ERTS_MSACC_IS_ENABLED_CACHED())                         \
+        erts_msacc_set_state_um__(__erts_msacc_cache, state, 1)
+#define ERTS_MSACC_PUSH_AND_SET_STATE_CACHED(state) \
+    ERTS_MSACC_PUSH_STATE_CACHED(); ERTS_MSACC_SET_STATE_CACHED(state)
+#define ERTS_MSACC_POP_STATE()                                          \
+    if (ERTS_MSACC_IS_ENABLED_CACHED())                                 \
+        erts_msacc_set_state_um__(__erts_msacc_cache, __erts_msacc_state, 0)
+
+/* Only use these defines when we know that we have in a managed thread */
+#define ERTS_MSACC_PUSH_STATE_M()                         \
+    ERTS_MSACC_DECLARE_CACHE();                           \
+    ERTS_MSACC_PUSH_STATE_CACHED_M()
+#define ERTS_MSACC_PUSH_STATE_CACHED_M()                                \
+    __erts_msacc_state = ERTS_MSACC_IS_ENABLED_CACHED() ?    \
+        erts_msacc_get_state_m__(__erts_msacc_cache) : ERTS_MSACC_STATE_OTHER
+#define ERTS_MSACC_SET_STATE_M(state)                   \
+    ERTS_MSACC_DECLARE_CACHE();                         \
+    ERTS_MSACC_SET_STATE_CACHED_M(state)
+#define ERTS_MSACC_SET_STATE_CACHED_M(state)            \
+    if (ERTS_MSACC_IS_ENABLED_CACHED())      \
+        erts_msacc_set_state_m__(__erts_msacc_cache, state, 1)
+#define ERTS_MSACC_POP_STATE_M()                                  \
+    if (ERTS_MSACC_IS_ENABLED_CACHED())                      \
+        erts_msacc_set_state_m__(__erts_msacc_cache, __erts_msacc_state, 0)
+#define ERTS_MSACC_PUSH_AND_SET_STATE_M(state)                    \
+    ERTS_MSACC_PUSH_STATE_M(); ERTS_MSACC_SET_STATE_CACHED_M(state)
+
+ERTS_MSACC_INLINE
+void erts_msacc_set_state_um__(ErtsMsAcc *msacc,Uint state,int increment);
+ERTS_MSACC_INLINE
+void erts_msacc_set_state_m__(ErtsMsAcc *msacc,Uint state,int increment);
+
+ERTS_MSACC_INLINE
+Uint erts_msacc_get_state_um__(ErtsMsAcc *msacc);
+ERTS_MSACC_INLINE
+Uint erts_msacc_get_state_m__(ErtsMsAcc *msacc);
+
+
+#if ERTS_GLB_INLINE_INCL_FUNC_DEF
+
+ERTS_MSACC_INLINE
+Uint erts_msacc_get_state_um__(ErtsMsAcc *msacc) {
+    Uint state;
+    if (msacc->unmanaged)
+        erts_mtx_lock(&msacc->mtx);
+    state = msacc->state;
+    if (msacc->unmanaged)
+        erts_mtx_unlock(&msacc->mtx);
+    return state;
+}
+
+ERTS_MSACC_INLINE
+Uint erts_msacc_get_state_m__(ErtsMsAcc *msacc) {
+    return msacc->state;
+}
+
+ERTS_MSACC_INLINE
+void erts_msacc_set_state_um__(ErtsMsAcc *msacc, Uint new_state, int increment) {
+    if (ERTS_UNLIKELY(msacc->unmanaged)) {
+        erts_mtx_lock(&msacc->mtx);
+        msacc->state = new_state;
+        if (ERTS_LIKELY(!msacc->perf_counter)) {
+            erts_mtx_unlock(&msacc->mtx);
+            return;
+        }
+    }
+
+    erts_msacc_set_state_m__(msacc,new_state,increment);
+
+    if (ERTS_UNLIKELY(msacc->unmanaged))
+        erts_mtx_unlock(&msacc->mtx);
+}
+
+ERTS_MSACC_INLINE
+void erts_msacc_set_state_m__(ErtsMsAcc *msacc, Uint new_state, int increment) {
+    ErtsSysHrTime prev_perf_counter;
+    Sint64 diff;
+
+    if (new_state == msacc->state)
+        return;
+
+    prev_perf_counter = msacc->perf_counter;
+    sys_perf_counter(&msacc->perf_counter);
+    diff = msacc->perf_counter - prev_perf_counter;
+    ASSERT(diff >= 0);
+    msacc->perf_counters[msacc->state] += diff;
+#ifdef ERTS_MSACC_STATE_COUNTERS
+    msacc->state_counters[new_state] += increment;
+#endif
+    msacc->state = new_state;
+}
+
+#endif /* ERTS_GLB_INLINE_INCL_FUNC_DEF */
+
+#else
+
+#define ERTS_MSACC_IS_ENABLED() 0
+#define erts_msacc_early_init()
+#define erts_msacc_init()
+#define erts_msacc_init_thread(type, id, liberty)
+#define ERTS_MSACC_PUSH_STATE()
+#define ERTS_MSACC_PUSH_STATE_CACHED()
+#define ERTS_MSACC_POP_STATE()
+#define ERTS_MSACC_SET_STATE(state)
+#define ERTS_MSACC_SET_STATE_CACHED(state)
+#define ERTS_MSACC_PUSH_AND_SET_STATE(state)
+#define ERTS_MSACC_PUSH_AND_SET_STATE_CACHED(state)
+#define ERTS_MSACC_UPDATE_CACHE()
+#define ERTS_MSACC_IS_ENABLED_CACHED()
+#define ERTS_MSACC_DECLARE_CACHE()
+#define ERTS_MSACC_PUSH_STATE_M()
+#define ERTS_MSACC_PUSH_STATE_CACHED_M()
+#define ERTS_MSACC_SET_STATE_CACHED_M(state)
+#define ERTS_MSACC_POP_STATE_M()
+#define ERTS_MSACC_PUSH_AND_SET_STATE_M(state)
+
+
+#endif /* ERTS_ENABLE_MSACC */
+
+#ifndef ERTS_MSACC_EXTENDED_STATES
+
+#define ERTS_MSACC_PUSH_STATE_X()
+#define ERTS_MSACC_POP_STATE_X()
+#define ERTS_MSACC_SET_STATE_X(state)
+#define ERTS_MSACC_SET_STATE_M_X(state)
+#define ERTS_MSACC_SET_STATE_CACHED_X(state)
+#define ERTS_MSACC_PUSH_AND_SET_STATE_X(state)
+#define ERTS_MSACC_PUSH_AND_SET_STATE_CACHED_X(state)
+#define ERTS_MSACC_UPDATE_CACHE_X()
+#define ERTS_MSACC_IS_ENABLED_CACHED_X() 0
+#define ERTS_MSACC_DECLARE_CACHE_X()
+#define ERTS_MSACC_PUSH_STATE_M_X()
+#define ERTS_MSACC_PUSH_STATE_CACHED_M_X()
+#define ERTS_MSACC_SET_STATE_CACHED_M_X(state)
+#define ERTS_MSACC_POP_STATE_M_X()
+#define ERTS_MSACC_PUSH_AND_SET_STATE_M_X(state)
+
+#else
+
+#define ERTS_MSACC_PUSH_STATE_X() ERTS_MSACC_PUSH_STATE()
+#define ERTS_MSACC_POP_STATE_X() ERTS_MSACC_POP_STATE()
+#define ERTS_MSACC_SET_STATE_X(state) ERTS_MSACC_SET_STATE(state)
+#define ERTS_MSACC_SET_STATE_M_X(state) ERTS_MSACC_SET_STATE_M(state)
+#define ERTS_MSACC_SET_STATE_CACHED_X(state) ERTS_MSACC_SET_STATE_CACHED(state)
+#define ERTS_MSACC_PUSH_AND_SET_STATE_X(state) ERTS_MSACC_PUSH_AND_SET_STATE(state)
+#define ERTS_MSACC_PUSH_AND_SET_STATE_CACHED_X(state) ERTS_MSACC_PUSH_AND_SET_STATE_CACHED(state)
+#define ERTS_MSACC_UPDATE_CACHE_X() ERTS_MSACC_UPDATE_CACHE()
+#define ERTS_MSACC_IS_ENABLED_CACHED_X() ERTS_MSACC_IS_ENABLED_CACHED()
+#define ERTS_MSACC_DECLARE_CACHE_X() ERTS_MSACC_DECLARE_CACHE()
+#define ERTS_MSACC_PUSH_STATE_M_X() ERTS_MSACC_PUSH_STATE_M()
+#define ERTS_MSACC_PUSH_STATE_CACHED_M_X() ERTS_MSACC_PUSH_STATE_CACHED_M()
+#define ERTS_MSACC_SET_STATE_CACHED_M_X(state) ERTS_MSACC_SET_STATE_CACHED_M(state)
+#define ERTS_MSACC_POP_STATE_M_X() ERTS_MSACC_POP_STATE_M()
+#define ERTS_MSACC_PUSH_AND_SET_STATE_M_X(state) ERTS_MSACC_PUSH_AND_SET_STATE_M(state)
+
+#endif /* !ERTS_MSACC_EXTENDED_STATES */
+
+#endif /* ERL_MSACC_H__ */