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, 41 insertions, 2 deletions

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index a0979c7b0e..14b81a0a6e 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -113,6 +113,9 @@ do {                                     \
 #define MAX(x, y) (((x) > (y)) ? (x) : (y))
 #endif
 
+#define GET_BIF_MODULE(p)  ((Eterm) (((Export *) p)->code[0]))
+#define GET_BIF_FUNCTION(p)  ((Eterm) (((Export *) p)->code[1]))
+#define GET_BIF_ARITY(p)  ((Eterm) (((Export *) p)->code[2]))
 #define GET_BIF_ADDRESS(p) ((BifFunction) (((Export *) p)->code[4]))
 #define TermWords(t) (((t) / (sizeof(BeamInstr)/sizeof(Eterm))) + !!((t) % (sizeof(BeamInstr)/sizeof(Eterm))))
 
@@ -1249,6 +1252,8 @@ void process_main(void)
     Uint64 start_time = 0;          /* Monitor long schedule */
     BeamInstr* start_time_i = NULL;
 
+    ERTS_MSACC_DECLARE_CACHE_X(); /* a cached value of the tsd pointer for msacc */
+
     ERL_BITS_DECLARE_STATEP; /* Has to be last declaration */
 
 
@@ -1302,6 +1307,8 @@ void process_main(void)
     ERTS_SMP_REQ_PROC_MAIN_LOCK(c_p);
     PROCESS_MAIN_CHK_LOCKS(c_p);
 
+    ERTS_MSACC_UPDATE_CACHE_X();
+
     if (erts_system_monitor_long_schedule != 0) {
 	start_time = erts_timestamp_millis();
 	start_time_i = c_p->i;
@@ -2741,11 +2748,21 @@ do {						\
      */
  OpCase(call_bif_e):
     {
-	Eterm (*bf)(Process*, Eterm*, BeamInstr*) = GET_BIF_ADDRESS(Arg(0));
+        Eterm (*bf)(Process*, Eterm*, BeamInstr*);
 	Eterm result;
 	BeamInstr *next;
 	ErlHeapFragment *live_hf_end;
 
+        if (ERTS_MSACC_IS_ENABLED_CACHED_X()) {
+            if (GET_BIF_MODULE(Arg(0)) == am_ets) {
+                ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_ETS);
+            } else {
+                ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_BIF);
+            }
+        }
+
+	bf = GET_BIF_ADDRESS(Arg(0));
+
 	PRE_BIF_SWAPOUT(c_p);
 	c_p->fcalls = FCALLS - 1;
 	if (FCALLS <= 0) {
@@ -2768,6 +2785,12 @@ do {						\
 	PROCESS_MAIN_CHK_LOCKS(c_p);
 	HTOP = HEAP_TOP(c_p);
 	FCALLS = c_p->fcalls;
+        /* We have to update the cache if we are enabled in order
+           to make sure no book keeping is done after we disabled
+           msacc. We don't always do this as it is quite expensive. */
+        if (ERTS_MSACC_IS_ENABLED_CACHED_X())
+            ERTS_MSACC_UPDATE_CACHE_X();
+	ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_EMULATOR);
 	if (is_value(result)) {
 	    r(0) = result;
 	    CHECK_TERM(r(0));
@@ -3452,6 +3475,8 @@ do {						\
 	    BifFunction vbf;
 	    ErlHeapFragment *live_hf_end;
 
+	    ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_NIF);
+
 	    DTRACE_NIF_ENTRY(c_p, (Eterm)I[-3], (Eterm)I[-2], (Uint)I[-1]);
 	    c_p->current = I-3; /* current and vbf set to please handle_error */ 
 	    SWAPOUT;
@@ -3476,6 +3501,8 @@ do {						\
 	    PROCESS_MAIN_CHK_LOCKS(c_p);
 	    ERTS_VERIFY_UNUSED_TEMP_ALLOC(c_p);
 
+	    ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_EMULATOR);
+
 	    DTRACE_NIF_RETURN(c_p, (Eterm)I[-3], (Eterm)I[-2], (Uint)I[-1]);
 	    goto apply_bif_or_nif_epilogue;
 	 
@@ -3490,6 +3517,13 @@ do {						\
 	     * code[3]: &&apply_bif
 	     * code[4]: Function pointer to BIF function
 	     */
+            if (ERTS_MSACC_IS_ENABLED_CACHED_X()) {
+                if ((Eterm)I[-3] == am_ets) {
+                    ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_ETS);
+                } else {
+                    ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_BIF);
+                }
+            }
 
 	    c_p->current = I-3;	/* In case we apply process_info/1,2 or load_nif/1 */
 	    c_p->i = I;		/* In case we apply check_process_code/2. */
@@ -3516,7 +3550,12 @@ do {						\
 		ERTS_VERIFY_UNUSED_TEMP_ALLOC(c_p);
 		PROCESS_MAIN_CHK_LOCKS(c_p);
 	    }
-
+            /* We have to update the cache if we are enabled in order
+               to make sure no book keeping is done after we disabled
+               msacc. We don't always do this as it is quite expensive. */
+            if (ERTS_MSACC_IS_ENABLED_CACHED_X())
+                ERTS_MSACC_UPDATE_CACHE_X();
+	    ERTS_MSACC_SET_STATE_CACHED_M_X(ERTS_MSACC_STATE_EMULATOR);
 	    DTRACE_BIF_RETURN(c_p, (Eterm)I[-3], (Eterm)I[-2], (Uint)I[-1]);
 
 	apply_bif_or_nif_epilogue: