ext/stackprof/stackprof.c in stackprof-0.2.17 vs ext/stackprof/stackprof.c in stackprof-0.2.18

@@ -5,20 +5,23 @@
   vim: noexpandtab shiftwidth=4 tabstop=8 softtabstop=4
 
 **********************************************************************/
 
 #include <ruby/ruby.h>
+#include <ruby/version.h>
 #include <ruby/debug.h>
 #include <ruby/st.h>
 #include <ruby/io.h>
 #include <ruby/intern.h>
 #include <signal.h>
 #include <sys/time.h>
+#include <time.h>
 #include <pthread.h>
 
 #define BUF_SIZE 2048
 #define MICROSECONDS_IN_SECOND 1000000
+#define NANOSECONDS_IN_SECOND 1000000000
 
 #define FAKE_FRAME_GC    INT2FIX(0)
 #define FAKE_FRAME_MARK  INT2FIX(1)
 #define FAKE_FRAME_SWEEP INT2FIX(2)
 
@@ -36,18 +39,64 @@
 	"(sweeping)",
 };
 
 #define TOTAL_FAKE_FRAMES (sizeof(fake_frame_cstrs) / sizeof(char *))
 
+#ifdef _POSIX_MONOTONIC_CLOCK
+  #define timestamp_t timespec
+  typedef struct timestamp_t timestamp_t;
+
+  static void capture_timestamp(timestamp_t *ts) {
+      clock_gettime(CLOCK_MONOTONIC, ts);
+  }
+
+  static int64_t delta_usec(timestamp_t *start, timestamp_t *end) {
+      int64_t result = MICROSECONDS_IN_SECOND * (end->tv_sec - start->tv_sec);
+      if (end->tv_nsec < start->tv_nsec) {
+	  result -= MICROSECONDS_IN_SECOND;
+	  result += (NANOSECONDS_IN_SECOND + end->tv_nsec - start->tv_nsec) / 1000;
+      } else {
+	  result += (end->tv_nsec - start->tv_nsec) / 1000;
+      }
+      return result;
+  }
+
+  static uint64_t timestamp_usec(timestamp_t *ts) {
+      return (MICROSECONDS_IN_SECOND * ts->tv_sec) + (ts->tv_nsec / 1000);
+  }
+#else
+  #define timestamp_t timeval
+  typedef struct timestamp_t timestamp_t;
+
+  static void capture_timestamp(timestamp_t *ts) {
+      gettimeofday(ts, NULL);
+  }
+
+  static int64_t delta_usec(timestamp_t *start, timestamp_t *end) {
+      struct timeval diff;
+      timersub(end, start, &diff);
+      return (MICROSECONDS_IN_SECOND * diff.tv_sec) + diff.tv_usec;
+  }
+
+  static uint64_t timestamp_usec(timestamp_t *ts) {
+      return (MICROSECONDS_IN_SECOND * ts.tv_sec) + diff.tv_usec
+  }
+#endif
+
 typedef struct {
     size_t total_samples;
     size_t caller_samples;
     size_t seen_at_sample_number;
     st_table *edges;
     st_table *lines;
 } frame_data_t;
 
+typedef struct {
+    uint64_t timestamp_usec;
+    int64_t delta_usec;
+} sample_time_t;
+
 static struct {
     int running;
     int raw;
     int aggregate;
 
@@ -60,14 +109,14 @@
     VALUE *raw_samples;
     size_t raw_samples_len;
     size_t raw_samples_capa;
     size_t raw_sample_index;
 
-    struct timeval last_sample_at;
-    int *raw_timestamp_deltas;
-    size_t raw_timestamp_deltas_len;
-    size_t raw_timestamp_deltas_capa;
+    struct timestamp_t last_sample_at;
+    sample_time_t *raw_sample_times;
+    size_t raw_sample_times_len;
+    size_t raw_sample_times_capa;
 
     size_t overall_signals;
     size_t overall_samples;
     size_t during_gc;
     size_t unrecorded_gc_samples;
@@ -75,18 +124,21 @@
     size_t unrecorded_gc_sweeping_samples;
     st_table *frames;
 
     VALUE fake_frame_names[TOTAL_FAKE_FRAMES];
     VALUE empty_string;
+
+    int buffer_count;
+    sample_time_t buffer_time;
     VALUE frames_buffer[BUF_SIZE];
     int lines_buffer[BUF_SIZE];
 } _stackprof;
 
 static VALUE sym_object, sym_wall, sym_cpu, sym_custom, sym_name, sym_file, sym_line;
 static VALUE sym_samples, sym_total_samples, sym_missed_samples, sym_edges, sym_lines;
 static VALUE sym_version, sym_mode, sym_interval, sym_raw, sym_metadata, sym_frames, sym_ignore_gc, sym_out;
-static VALUE sym_aggregate, sym_raw_timestamp_deltas, sym_state, sym_marking, sym_sweeping;
+static VALUE sym_aggregate, sym_raw_sample_timestamps, sym_raw_timestamp_deltas, sym_state, sym_marking, sym_sweeping;
 static VALUE sym_gc_samples, objtracer;
 static VALUE gc_hook;
 static VALUE rb_mStackProf;
 
 static void stackprof_newobj_handler(VALUE, void*);
@@ -172,11 +224,11 @@
     _stackprof.ignore_gc = ignore_gc;
     _stackprof.metadata = metadata;
     _stackprof.out = out;
 
     if (raw) {
-	gettimeofday(&_stackprof.last_sample_at, NULL);
+	capture_timestamp(&_stackprof.last_sample_at);
     }
 
     return Qtrue;
 }
 
@@ -207,17 +259,23 @@
     }
 
     return Qtrue;
 }
 
+#if SIZEOF_VOIDP == SIZEOF_LONG
+#  define PTR2NUM(x) (LONG2NUM((long)(x)))
+#else
+#  define PTR2NUM(x) (LL2NUM((LONG_LONG)(x)))
+#endif
+
 static int
 frame_edges_i(st_data_t key, st_data_t val, st_data_t arg)
 {
     VALUE edges = (VALUE)arg;
 
     intptr_t weight = (intptr_t)val;
-    rb_hash_aset(edges, rb_obj_id((VALUE)key), INT2FIX(weight));
+    rb_hash_aset(edges, PTR2NUM(key), INT2FIX(weight));
     return ST_CONTINUE;
 }
 
 static int
 frame_lines_i(st_data_t key, st_data_t val, st_data_t arg)
@@ -240,11 +298,11 @@
     VALUE results = (VALUE)arg;
     VALUE details = rb_hash_new();
     VALUE name, file, edges, lines;
     VALUE line;
 
-    rb_hash_aset(results, rb_obj_id(frame), details);
+    rb_hash_aset(results, PTR2NUM(frame), details);
 
     if (FIXNUM_P(frame)) {
 	name = _stackprof.fake_frame_names[FIX2INT(frame)];
 	file = _stackprof.empty_string;
 	line = INT2FIX(0);
@@ -312,19 +370,19 @@
     st_free_table(_stackprof.frames);
     _stackprof.frames = NULL;
 
     if (_stackprof.raw && _stackprof.raw_samples_len) {
 	size_t len, n, o;
-	VALUE raw_timestamp_deltas;
+	VALUE raw_sample_timestamps, raw_timestamp_deltas;
 	VALUE raw_samples = rb_ary_new_capa(_stackprof.raw_samples_len);
 
 	for (n = 0; n < _stackprof.raw_samples_len; n++) {
 	    len = (size_t)_stackprof.raw_samples[n];
 	    rb_ary_push(raw_samples, SIZET2NUM(len));
 
 	    for (o = 0, n++; o < len; n++, o++)
-		rb_ary_push(raw_samples, rb_obj_id(_stackprof.raw_samples[n]));
+		rb_ary_push(raw_samples, PTR2NUM(_stackprof.raw_samples[n]));
 	    rb_ary_push(raw_samples, SIZET2NUM((size_t)_stackprof.raw_samples[n]));
 	}
 
 	free(_stackprof.raw_samples);
 	_stackprof.raw_samples = NULL;
@@ -332,21 +390,24 @@
 	_stackprof.raw_samples_capa = 0;
 	_stackprof.raw_sample_index = 0;
 
 	rb_hash_aset(results, sym_raw, raw_samples);
 
-	raw_timestamp_deltas = rb_ary_new_capa(_stackprof.raw_timestamp_deltas_len);
+	raw_sample_timestamps = rb_ary_new_capa(_stackprof.raw_sample_times_len);
+	raw_timestamp_deltas = rb_ary_new_capa(_stackprof.raw_sample_times_len);
 
-	for (n = 0; n < _stackprof.raw_timestamp_deltas_len; n++) {
-	    rb_ary_push(raw_timestamp_deltas, INT2FIX(_stackprof.raw_timestamp_deltas[n]));
+	for (n = 0; n < _stackprof.raw_sample_times_len; n++) {
+	    rb_ary_push(raw_sample_timestamps, ULL2NUM(_stackprof.raw_sample_times[n].timestamp_usec));
+	    rb_ary_push(raw_timestamp_deltas, LL2NUM(_stackprof.raw_sample_times[n].delta_usec));
 	}
 
-	free(_stackprof.raw_timestamp_deltas);
-	_stackprof.raw_timestamp_deltas = NULL;
-	_stackprof.raw_timestamp_deltas_len = 0;
-	_stackprof.raw_timestamp_deltas_capa = 0;
+	free(_stackprof.raw_sample_times);
+	_stackprof.raw_sample_times = NULL;
+	_stackprof.raw_sample_times_len = 0;
+	_stackprof.raw_sample_times_capa = 0;
 
+	rb_hash_aset(results, sym_raw_sample_timestamps, raw_sample_timestamps);
 	rb_hash_aset(results, sym_raw_timestamp_deltas, raw_timestamp_deltas);
 
 	_stackprof.raw = 0;
     }
 
@@ -422,18 +483,18 @@
 {
     st_update(table, key, numtable_increment_callback, (st_data_t)increment);
 }
 
 void
-stackprof_record_sample_for_stack(int num, int timestamp_delta)
+stackprof_record_sample_for_stack(int num, uint64_t sample_timestamp, int64_t timestamp_delta)
 {
     int i, n;
     VALUE prev_frame = Qnil;
 
     _stackprof.overall_samples++;
 
-    if (_stackprof.raw) {
+    if (_stackprof.raw && num > 0) {
 	int found = 0;
 
 	/* If there's no sample buffer allocated, then allocate one.  The buffer
 	 * format is the number of frames (num), then the list of frames (from
 	 * `_stackprof.raw_samples`), followed by the number of times this
@@ -481,24 +542,27 @@
 	    }
 	    _stackprof.raw_samples[_stackprof.raw_samples_len++] = (VALUE)1;
 	}
 
 	/* If there's no timestamp delta buffer, allocate one */
-	if (!_stackprof.raw_timestamp_deltas) {
-	    _stackprof.raw_timestamp_deltas_capa = 100;
-	    _stackprof.raw_timestamp_deltas = malloc(sizeof(int) * _stackprof.raw_timestamp_deltas_capa);
-	    _stackprof.raw_timestamp_deltas_len = 0;
+	if (!_stackprof.raw_sample_times) {
+	    _stackprof.raw_sample_times_capa = 100;
+	    _stackprof.raw_sample_times = malloc(sizeof(sample_time_t) * _stackprof.raw_sample_times_capa);
+	    _stackprof.raw_sample_times_len = 0;
 	}
 
 	/* Double the buffer size if it's too small */
-	while (_stackprof.raw_timestamp_deltas_capa <= _stackprof.raw_timestamp_deltas_len + 1) {
-	    _stackprof.raw_timestamp_deltas_capa *= 2;
-	    _stackprof.raw_timestamp_deltas = realloc(_stackprof.raw_timestamp_deltas, sizeof(int) * _stackprof.raw_timestamp_deltas_capa);
+	while (_stackprof.raw_sample_times_capa <= _stackprof.raw_sample_times_len + 1) {
+	    _stackprof.raw_sample_times_capa *= 2;
+	    _stackprof.raw_sample_times = realloc(_stackprof.raw_sample_times, sizeof(sample_time_t) * _stackprof.raw_sample_times_capa);
 	}
 
-	/* Store the time delta (which is the amount of time between samples) */
-	_stackprof.raw_timestamp_deltas[_stackprof.raw_timestamp_deltas_len++] = timestamp_delta;
+	/* Store the time delta (which is the amount of microseconds between samples). */
+	_stackprof.raw_sample_times[_stackprof.raw_sample_times_len++] = (sample_time_t) {
+	    .timestamp_usec = sample_timestamp,
+	    .delta_usec = timestamp_delta,
+        };
     }
 
     for (i = 0; i < num; i++) {
 	int line = _stackprof.lines_buffer[i];
 	VALUE frame = _stackprof.frames_buffer[i];
@@ -527,99 +591,137 @@
 
 	prev_frame = frame;
     }
 
     if (_stackprof.raw) {
-	gettimeofday(&_stackprof.last_sample_at, NULL);
+	capture_timestamp(&_stackprof.last_sample_at);
     }
 }
 
+// buffer the current profile frames
+// This must be async-signal-safe
+// Returns immediately if another set of frames are already in the buffer
 void
-stackprof_record_sample()
+stackprof_buffer_sample(void)
 {
-    int timestamp_delta = 0;
+    if (_stackprof.buffer_count > 0) {
+	// Another sample is already pending
+	return;
+    }
+
+    uint64_t start_timestamp = 0;
+    int64_t timestamp_delta = 0;
     int num;
     if (_stackprof.raw) {
-	struct timeval t;
-	struct timeval diff;
-	gettimeofday(&t, NULL);
-	timersub(&t, &_stackprof.last_sample_at, &diff);
-	timestamp_delta = (1000 * diff.tv_sec) + diff.tv_usec;
+	struct timestamp_t t;
+	capture_timestamp(&t);
+	start_timestamp = timestamp_usec(&t);
+	timestamp_delta = delta_usec(&t, &_stackprof.last_sample_at);
     }
+
     num = rb_profile_frames(0, sizeof(_stackprof.frames_buffer) / sizeof(VALUE), _stackprof.frames_buffer, _stackprof.lines_buffer);
-    stackprof_record_sample_for_stack(num, timestamp_delta);
+
+    _stackprof.buffer_count = num;
+    _stackprof.buffer_time.timestamp_usec = start_timestamp;
+    _stackprof.buffer_time.delta_usec = timestamp_delta;
 }
 
 void
-stackprof_record_gc_samples()
+stackprof_record_gc_samples(void)
 {
-    int delta_to_first_unrecorded_gc_sample = 0;
-    int i;
+    int64_t delta_to_first_unrecorded_gc_sample = 0;
+    uint64_t start_timestamp = 0;
+    size_t i;
     if (_stackprof.raw) {
-	struct timeval t;
-	struct timeval diff;
-	gettimeofday(&t, NULL);
-	timersub(&t, &_stackprof.last_sample_at, &diff);
+	struct timestamp_t t;
+	capture_timestamp(&t);
+	start_timestamp = timestamp_usec(&t);
 
 	// We don't know when the GC samples were actually marked, so let's
 	// assume that they were marked at a perfectly regular interval.
-	delta_to_first_unrecorded_gc_sample = (1000 * diff.tv_sec + diff.tv_usec) - (_stackprof.unrecorded_gc_samples - 1) * NUM2LONG(_stackprof.interval);
+	delta_to_first_unrecorded_gc_sample = delta_usec(&t, &_stackprof.last_sample_at) - (_stackprof.unrecorded_gc_samples - 1) * NUM2LONG(_stackprof.interval);
 	if (delta_to_first_unrecorded_gc_sample < 0) {
 	    delta_to_first_unrecorded_gc_sample = 0;
 	}
     }
 
-
     for (i = 0; i < _stackprof.unrecorded_gc_samples; i++) {
-	int timestamp_delta = i == 0 ? delta_to_first_unrecorded_gc_sample : NUM2LONG(_stackprof.interval);
+	int64_t timestamp_delta = i == 0 ? delta_to_first_unrecorded_gc_sample : NUM2LONG(_stackprof.interval);
 
       if (_stackprof.unrecorded_gc_marking_samples) {
         _stackprof.frames_buffer[0] = FAKE_FRAME_MARK;
         _stackprof.lines_buffer[0] = 0;
         _stackprof.frames_buffer[1] = FAKE_FRAME_GC;
         _stackprof.lines_buffer[1] = 0;
         _stackprof.unrecorded_gc_marking_samples--;
 
-        stackprof_record_sample_for_stack(2, timestamp_delta);
+        stackprof_record_sample_for_stack(2, start_timestamp, timestamp_delta);
       } else if (_stackprof.unrecorded_gc_sweeping_samples) {
         _stackprof.frames_buffer[0] = FAKE_FRAME_SWEEP;
         _stackprof.lines_buffer[0] = 0;
         _stackprof.frames_buffer[1] = FAKE_FRAME_GC;
         _stackprof.lines_buffer[1] = 0;
 
         _stackprof.unrecorded_gc_sweeping_samples--;
 
-        stackprof_record_sample_for_stack(2, timestamp_delta);
+        stackprof_record_sample_for_stack(2, start_timestamp, timestamp_delta);
       } else {
         _stackprof.frames_buffer[0] = FAKE_FRAME_GC;
         _stackprof.lines_buffer[0] = 0;
-        stackprof_record_sample_for_stack(1, timestamp_delta);
+        stackprof_record_sample_for_stack(1, start_timestamp, timestamp_delta);
       }
     }
     _stackprof.during_gc += _stackprof.unrecorded_gc_samples;
     _stackprof.unrecorded_gc_samples = 0;
     _stackprof.unrecorded_gc_marking_samples = 0;
     _stackprof.unrecorded_gc_sweeping_samples = 0;
 }
 
+// record the sample previously buffered by stackprof_buffer_sample
 static void
-stackprof_gc_job_handler(void *data)
+stackprof_record_buffer(void)
 {
+    stackprof_record_sample_for_stack(_stackprof.buffer_count, _stackprof.buffer_time.timestamp_usec, _stackprof.buffer_time.delta_usec);
+
+    // reset the buffer
+    _stackprof.buffer_count = 0;
+}
+
+static void
+stackprof_sample_and_record(void)
+{
+    stackprof_buffer_sample();
+    stackprof_record_buffer();
+}
+
+static void
+stackprof_job_record_gc(void *data)
+{
     if (!_stackprof.running) return;
 
     stackprof_record_gc_samples();
 }
 
+#ifdef USE_POSTPONED_JOB
 static void
-stackprof_job_handler(void *data)
+stackprof_job_sample_and_record(void *data)
 {
     if (!_stackprof.running) return;
 
-    stackprof_record_sample();
+    stackprof_sample_and_record();
 }
+#endif
 
 static void
+stackprof_job_record_buffer(void *data)
+{
+    if (!_stackprof.running) return;
+
+    stackprof_record_buffer();
+}
+
+static void
 stackprof_signal_handler(int sig, siginfo_t *sinfo, void *ucontext)
 {
     static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
 
     _stackprof.overall_signals++;
@@ -634,16 +736,20 @@
 	    _stackprof.unrecorded_gc_marking_samples++;
 	} else if (mode == sym_sweeping) {
 	    _stackprof.unrecorded_gc_sweeping_samples++;
 	}
 	_stackprof.unrecorded_gc_samples++;
-	rb_postponed_job_register_one(0, stackprof_gc_job_handler, (void*)0);
+	rb_postponed_job_register_one(0, stackprof_job_record_gc, (void*)0);
     } else {
 #ifdef USE_POSTPONED_JOB
-	rb_postponed_job_register_one(0, stackprof_job_handler, (void*)0);
+	rb_postponed_job_register_one(0, stackprof_job_sample_and_record, (void*)0);
 #else
-	stackprof_job_handler(0);
+	// Buffer a sample immediately, if an existing sample exists this will
+	// return immediately
+	stackprof_buffer_sample();
+	// Enqueue a job to record the sample
+	rb_postponed_job_register_one(0, stackprof_job_record_buffer, (void*)0);
 #endif
     }
     pthread_mutex_unlock(&lock);
 }
 
@@ -651,21 +757,21 @@
 stackprof_newobj_handler(VALUE tpval, void *data)
 {
     _stackprof.overall_signals++;
     if (RTEST(_stackprof.interval) && _stackprof.overall_signals % NUM2LONG(_stackprof.interval))
 	return;
-    stackprof_job_handler(0);
+    stackprof_sample_and_record();
 }
 
 static VALUE
 stackprof_sample(VALUE self)
 {
     if (!_stackprof.running)
 	return Qfalse;
 
     _stackprof.overall_signals++;
-    stackprof_job_handler(0);
+    stackprof_sample_and_record();
     return Qtrue;
 }
 
 static int
 frame_mark_i(st_data_t key, st_data_t val, st_data_t arg)
@@ -740,10 +846,11 @@
     S(lines);
     S(version);
     S(mode);
     S(interval);
     S(raw);
+    S(raw_sample_timestamps);
     S(raw_timestamp_deltas);
     S(out);
     S(metadata);
     S(ignore_gc);
     S(frames);
@@ -762,12 +869,12 @@
     _stackprof.raw_samples = NULL;
     _stackprof.raw_samples_len = 0;
     _stackprof.raw_samples_capa = 0;
     _stackprof.raw_sample_index = 0;
 
-    _stackprof.raw_timestamp_deltas = NULL;
-    _stackprof.raw_timestamp_deltas_len = 0;
-    _stackprof.raw_timestamp_deltas_capa = 0;
+    _stackprof.raw_sample_times = NULL;
+    _stackprof.raw_sample_times_len = 0;
+    _stackprof.raw_sample_times_capa = 0;
 
     _stackprof.empty_string = rb_str_new_cstr("");
     rb_global_variable(&_stackprof.empty_string);
 
     for (i = 0; i < TOTAL_FAKE_FRAMES; i++) {