Merge branch 'pan/dtrace' into maint

* pan/dtrace: (22 commits)
  Use distinct function-entry probes for local and global calls
  Correct calculation of stack depth in call/return probes
  Add probes for all kind of calls
  Don't try to "clean up" generated fun names
  erl_process.c: Fix probe for process exit
  Remove code causing dialyzer warning from prim_file
  Add documentation for dyntrace and system_info changes
  Update slogan and add system_info for dynamic trace
  Update README's for dtrace and systemtap
  Rename dyntrace BIFs to more suiting names
  If VM probes are not enabled, short-circuit calls to probe BIFs
  beam_makeops: Add a simple preprocessor
  Ifdef all dynamic trace code
  Move dtrace erlang code and NIF into runtime_tools
  Correct some errors in the user tag spreading
  Change to more specific configure options for dtrace
  Add user tag spreading functionality to VM and use in file
  Update dtrace for changes in R15
  Add DTrace support for OS X, Solaris, and Linux (via SystemTap), 4/4
  Add DTrace support for OS X, Solaris, and Linux (via SystemTap), 3/4
  ...

OTP-10017

1 files changed, 32 insertions, 0 deletions

diff --git a/erts/emulator/beam/erl_async.c b/erts/emulator/beam/erl_async.c
index 8bca9ae582..f0e98b33a5 100644
--- a/erts/emulator/beam/erl_async.c
+++ b/erts/emulator/beam/erl_async.c
@@ -26,6 +26,7 @@
 #include "erl_threads.h"
 #include "erl_thr_queue.h"
 #include "erl_async.h"
+#include "dtrace-wrapper.h"
 
 #define ERTS_MAX_ASYNC_READY_CALLS_IN_SEQ 20
 
@@ -121,6 +122,14 @@ typedef struct {
 #endif
 } ErtsAsyncData;
 
+/*
+ * Some compilers, e.g. GCC 4.2.1 and -O3, will optimize away DTrace
+ * calls if they're the last thing in the function.  :-(
+ * Many thanks to Trond Norbye, via:
+ * https://github.com/memcached/memcached/commit/6298b3978687530bc9d219b6ac707a1b681b2a46
+ */
+static unsigned gcc_optimizer_hack = 0;
+
 int erts_async_max_threads; /* Initialized by erl_init.c */
 int erts_async_thread_suggested_stack_size; /* Initialized by erl_init.c */
 
@@ -244,6 +253,8 @@ erts_get_async_ready_queue(Uint sched_id)
 
 static ERTS_INLINE void async_add(ErtsAsync *a, ErtsAsyncQ* q)
 {
+    int len;
+
     if (is_internal_port(a->port)) {
 #if ERTS_USE_ASYNC_READY_Q
 	ErtsAsyncReadyQ *arq = async_ready_q(a->sched_id);
@@ -259,6 +270,17 @@ static ERTS_INLINE void async_add(ErtsAsync *a, ErtsAsyncQ* q)
 #endif
 
     erts_thr_q_enqueue(&q->thr_q, a);
+#ifdef USE_VM_PROBES
+    if (DTRACE_ENABLED(aio_pool_add)) {
+        DTRACE_CHARBUF(port_str, 16);
+
+        erts_snprintf(port_str, sizeof(port_str), "%T", a->port);
+        /* DTRACE TODO: Get the queue length from erts_thr_q_enqueue() ? */
+        len = -1;
+        DTRACE2(aio_pool_add, port_str, len);
+    }
+#endif
+    gcc_optimizer_hack++;
 }
 
 static ERTS_INLINE ErtsAsync *async_get(ErtsThrQ_t *q,
@@ -269,6 +291,7 @@ static ERTS_INLINE ErtsAsync *async_get(ErtsThrQ_t *q,
     int saved_fin_deq = 0;
     ErtsThrQFinDeQ_t fin_deq;
 #endif
+    int len;
 
     while (1) {
 	ErtsAsync *a = (ErtsAsync *) erts_thr_q_dequeue(q);
@@ -280,7 +303,16 @@ static ERTS_INLINE ErtsAsync *async_get(ErtsThrQ_t *q,
 	    if (saved_fin_deq)
 		erts_thr_q_append_finalize_dequeue_data(&a->q.fin_deq, &fin_deq);
 #endif
+#ifdef USE_VM_PROBES
+            if (DTRACE_ENABLED(aio_pool_get)) {
+                DTRACE_CHARBUF(port_str, 16);
 
+                erts_snprintf(port_str, sizeof(port_str), "%T", a->port);
+                /* DTRACE TODO: Get the length from erts_thr_q_dequeue() ? */
+                len = -1;
+                DTRACE2(aio_pool_get, port_str, len);
+            }
+#endif
 	    return a;
 	}