Implement opt.stats_interval and the _opts options.

Add options stats_interval and stats_interval_opts to allow interval based stats
printing.  This provides an easy way to collect stats without code changes,
because opt.stats_print may not work (some binaries never exit).

Makefile.in

@@ -191,6 +191,7 @@ TESTS_UNIT := \
 	$(srcroot)test/unit/buf_writer.c \
 	$(srcroot)test/unit/cache_bin.c \
 	$(srcroot)test/unit/ckh.c \
+	$(srcroot)test/unit/counter.c \
 	$(srcroot)test/unit/decay.c \
 	$(srcroot)test/unit/div.c \
 	$(srcroot)test/unit/emitter.c \

doc/jemalloc.xml.in

@@ -1185,6 +1185,41 @@ mallctl("arena." STRINGIFY(MALLCTL_ARENAS_ALL) ".decay",
         enabled.  The default is <quote></quote>.</para></listitem>
       </varlistentry>
 
+      <varlistentry id="opt.stats_interval">
+        <term>
+          <mallctl>opt.stats_interval</mallctl>
+          (<type>int64_t</type>)
+          <literal>r-</literal>
+        </term>
+        <listitem><para>Average interval between statistics outputs, as measured
+        in bytes of allocation activity.  The actual interval may be sporadic
+        because decentralized event counters are used to avoid synchronization
+        bottlenecks.  The output may be triggered on any thread, which then
+        calls <function>malloc_stats_print()</function>.  <link
+        linkend="opt.stats_interval_opts"><mallctl>opt.stats_interval_opts</mallctl></link>
+        can be combined to specify output options.  By default,
+        interval-triggered stats output is disabled (encoded as
+        -1).</para></listitem>
+      </varlistentry>
+
+      <varlistentry id="opt.stats_interval_opts">
+        <term>
+          <mallctl>opt.stats_interval_opts</mallctl>
+          (<type>const char *</type>)
+          <literal>r-</literal>
+        </term>
+        <listitem><para>Options (the <parameter>opts</parameter> string) to pass
+        to the <function>malloc_stats_print()</function> for interval based
+	statistics printing (enabled
+        through <link
+        linkend="opt.stats_interval"><mallctl>opt.stats_interval</mallctl></link>). See
+        available options in <link
+        linkend="malloc_stats_print_opts"><function>malloc_stats_print()</function></link>.
+        Has no effect unless <link
+        linkend="opt.stats_interval"><mallctl>opt.stats_interval</mallctl></link> is
+        enabled.  The default is <quote></quote>.</para></listitem>
+      </varlistentry>
+
       <varlistentry id="opt.junk">
         <term>
           <mallctl>opt.junk</mallctl>

include/jemalloc/internal/counter.h

@@ -6,11 +6,11 @@
 typedef struct counter_accum_s {
 #ifndef JEMALLOC_ATOMIC_U64
 	malloc_mutex_t	mtx;
-	uint64_t	accumbytes;
+	uint64_t accumbytes;
 #else
-	atomic_u64_t	accumbytes;
+	atomic_u64_t accumbytes;
 #endif
-	uint64_t	interval;
+	uint64_t interval;
 } counter_accum_t;
 
 JEMALLOC_ALWAYS_INLINE bool
@@ -52,7 +52,7 @@ counter_accum(tsdn_t *tsdn, counter_accum_t *counter, uint64_t accumbytes) {
 }
 
 JEMALLOC_ALWAYS_INLINE void
-counter_rollback(tsdn_t *tsdn, counter_accum_t *counter, size_t usize) {
+counter_rollback(tsdn_t *tsdn, counter_accum_t *counter, uint64_t bytes) {
 	/*
 	 * Cancel out as much of the excessive accumbytes increase as possible
 	 * without underflowing.  Interval-triggered events occur slightly more
@@ -63,16 +63,14 @@ counter_rollback(tsdn_t *tsdn, counter_accum_t *counter, size_t usize) {
 	a0 = atomic_load_u64(&counter->accumbytes,
 	    ATOMIC_RELAXED);
 	do {
-		a1 = (a0 >= SC_LARGE_MINCLASS - usize)
+		a1 = (a0 >= bytes) ? a0 - bytes : 0;
-		    ? a0 - (SC_LARGE_MINCLASS - usize) : 0;
 	} while (!atomic_compare_exchange_weak_u64(
 	    &counter->accumbytes, &a0, a1, ATOMIC_RELAXED,
 	    ATOMIC_RELAXED));
 #else
 	malloc_mutex_lock(tsdn, &counter->mtx);
 	a0 = counter->accumbytes;
-	a1 = (a0 >= SC_LARGE_MINCLASS - usize)
+	a1 = (a0 >= bytes) ?  a0 - bytes : 0;
-	    ?  a0 - (SC_LARGE_MINCLASS - usize) : 0;
 	counter->accumbytes = a1;
 	malloc_mutex_unlock(tsdn, &counter->mtx);
 #endif

include/jemalloc/internal/emitter.h

@@ -22,6 +22,7 @@ typedef enum emitter_type_e emitter_type_t;
 enum emitter_type_e {
 	emitter_type_bool,
 	emitter_type_int,
+	emitter_type_int64,
 	emitter_type_unsigned,
 	emitter_type_uint32,
 	emitter_type_uint64,
@@ -149,6 +150,9 @@ emitter_print_value(emitter_t *emitter, emitter_justify_t justify, int width,
 	case emitter_type_int:
 		EMIT_SIMPLE(int, "%d")
 		break;
+	case emitter_type_int64:
+		EMIT_SIMPLE(int64_t, "%" FMTd64)
+		break;
 	case emitter_type_unsigned:
 		EMIT_SIMPLE(unsigned, "%u")
 		break;

include/jemalloc/internal/stats.h

@@ -24,8 +24,26 @@ enum {
 extern bool opt_stats_print;
 extern char opt_stats_print_opts[stats_print_tot_num_options+1];
 
+/* Utilities for stats_interval. */
+extern int64_t opt_stats_interval;
+extern char opt_stats_interval_opts[stats_print_tot_num_options+1];
+
+#define STATS_INTERVAL_DEFAULT -1
+/*
+ * Batch-increment the counter to reduce synchronization overhead.  Each thread
+ * merges after (interval >> LG_BATCH_SIZE) bytes of allocations; also limit the
+ * BATCH_MAX for accuracy when the interval is huge (which is expected).
+ */
+#define STATS_INTERVAL_ACCUM_LG_BATCH_SIZE 6
+#define STATS_INTERVAL_ACCUM_BATCH_MAX (4 << 20)
+
+uint64_t stats_interval_accum_batch_size(void);
+bool stats_interval_accum(tsd_t *tsd, uint64_t bytes);
+
 /* Implements je_malloc_stats_print. */
 void stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
     const char *opts);
 
+bool stats_boot(void);
+
 #endif /* JEMALLOC_INTERNAL_STATS_H */

include/jemalloc/internal/thread_event.h

@@ -36,7 +36,8 @@ void tsd_thread_event_init(tsd_t *tsd);
  */
 #define ITERATE_OVER_ALL_EVENTS						\
     E(tcache_gc,	(TCACHE_GC_INCR_BYTES > 0))			\
-    E(prof_sample,	(config_prof && opt_prof))
+    E(prof_sample,	(config_prof && opt_prof))	    		\
+    E(stats_interval,	(opt_stats_interval >= 0))
 
 #define E(event, condition)						\
     C(event##_event_wait)
@@ -46,7 +47,8 @@ void tsd_thread_event_init(tsd_t *tsd);
     C(thread_allocated)							\
     C(thread_allocated_last_event)					\
     ITERATE_OVER_ALL_EVENTS						\
-    C(prof_sample_last_event)
+    C(prof_sample_last_event)						\
+    C(stats_interval_last_event)
 
 /* Getters directly wrap TSD getters. */
 #define C(counter)							\

include/jemalloc/internal/tsd.h

@@ -87,6 +87,8 @@ typedef void (*test_callback_t)(int *);
     O(tcache_gc_event_wait,	uint64_t,		uint64_t)	\
     O(prof_sample_event_wait,	uint64_t,		uint64_t)	\
     O(prof_sample_last_event,	uint64_t,		uint64_t)	\
+    O(stats_interval_event_wait,	uint64_t,	uint64_t)	\
+    O(stats_interval_last_event,	uint64_t,	uint64_t)	\
     O(prof_tdata,		prof_tdata_t *,		prof_tdata_t *)	\
     O(prng_state,		uint64_t,		uint64_t)	\
     O(iarena,			arena_t *,		arena_t *)	\
@@ -118,6 +120,8 @@ typedef void (*test_callback_t)(int *);
     /* tcache_gc_event_wait */		THREAD_EVENT_MIN_START_WAIT,	\
     /* prof_sample_event_wait */	THREAD_EVENT_MIN_START_WAIT,	\
     /* prof_sample_last_event */	0,				\
+    /* stats_interval_event_wait */	THREAD_EVENT_MIN_START_WAIT,	\
+    /* stats_interval_last_event */	0,				\
     /* prof_tdata */		NULL,					\
     /* prng_state */		0,					\
     /* iarena */		NULL,					\

src/ctl.c

@@ -96,6 +96,8 @@ CTL_PROTO(opt_dirty_decay_ms)
 CTL_PROTO(opt_muzzy_decay_ms)
 CTL_PROTO(opt_stats_print)
 CTL_PROTO(opt_stats_print_opts)
+CTL_PROTO(opt_stats_interval)
+CTL_PROTO(opt_stats_interval_opts)
 CTL_PROTO(opt_junk)
 CTL_PROTO(opt_zero)
 CTL_PROTO(opt_utrace)
@@ -329,6 +331,8 @@ static const ctl_named_node_t opt_node[] = {
 	{NAME("muzzy_decay_ms"), CTL(opt_muzzy_decay_ms)},
 	{NAME("stats_print"),	CTL(opt_stats_print)},
 	{NAME("stats_print_opts"),	CTL(opt_stats_print_opts)},
+	{NAME("stats_interval"),	CTL(opt_stats_interval)},
+	{NAME("stats_interval_opts"),	CTL(opt_stats_interval_opts)},
 	{NAME("junk"),		CTL(opt_junk)},
 	{NAME("zero"),		CTL(opt_zero)},
 	{NAME("utrace"),	CTL(opt_utrace)},
@@ -1791,6 +1795,8 @@ CTL_RO_NL_GEN(opt_dirty_decay_ms, opt_dirty_decay_ms, ssize_t)
 CTL_RO_NL_GEN(opt_muzzy_decay_ms, opt_muzzy_decay_ms, ssize_t)
 CTL_RO_NL_GEN(opt_stats_print, opt_stats_print, bool)
 CTL_RO_NL_GEN(opt_stats_print_opts, opt_stats_print_opts, const char *)
+CTL_RO_NL_GEN(opt_stats_interval, opt_stats_interval, int64_t)
+CTL_RO_NL_GEN(opt_stats_interval_opts, opt_stats_interval_opts, const char *)
 CTL_RO_NL_CGEN(config_fill, opt_junk, opt_junk, const char *)
 CTL_RO_NL_CGEN(config_fill, opt_zero, opt_zero, bool)
 CTL_RO_NL_CGEN(config_utrace, opt_utrace, opt_utrace, bool)

src/jemalloc.c

@@ -775,8 +775,8 @@ malloc_ncpus(void) {
 }
 
 static void
-init_opt_stats_print_opts(const char *v, size_t vlen) {
+init_opt_stats_opts(const char *v, size_t vlen, char *dest) {
-	size_t opts_len = strlen(opt_stats_print_opts);
+	size_t opts_len = strlen(dest);
 	assert(opts_len <= stats_print_tot_num_options);
 
 	for (size_t i = 0; i < vlen; i++) {
@@ -787,16 +787,16 @@ init_opt_stats_print_opts(const char *v, size_t vlen) {
 		default: continue;
 		}
 
-		if (strchr(opt_stats_print_opts, v[i]) != NULL) {
+		if (strchr(dest, v[i]) != NULL) {
 			/* Ignore repeated. */
 			continue;
 		}
 
-		opt_stats_print_opts[opts_len++] = v[i];
+		dest[opts_len++] = v[i];
-		opt_stats_print_opts[opts_len] = '\0';
+		dest[opts_len] = '\0';
 		assert(opts_len <= stats_print_tot_num_options);
 	}
-	assert(opts_len == strlen(opt_stats_print_opts));
+	assert(opts_len == strlen(dest));
 }
 
 /* Reads the next size pair in a multi-sized option. */
@@ -1118,39 +1118,47 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 #define CONF_CHECK_MIN(um, min)	((um) < (min))
 #define CONF_DONT_CHECK_MAX(um, max)	false
 #define CONF_CHECK_MAX(um, max)	((um) > (max))
-#define CONF_HANDLE_T_U(t, o, n, min, max, check_min, check_max, clip)	\
+
+#define CONF_HANDLE_T(t, max_t, o, n, min, max, check_min, check_max, clip) \
 			if (CONF_MATCH(n)) {				\
-				uintmax_t um;				\
+				max_t mv;				\
 				char *end;				\
 									\
 				set_errno(0);				\
-				um = malloc_strtoumax(v, &end, 0);	\
+				mv = (max_t)malloc_strtoumax(v, &end, 0); \
 				if (get_errno() != 0 || (uintptr_t)end -\
 				    (uintptr_t)v != vlen) {		\
 					CONF_ERROR("Invalid conf value",\
 					    k, klen, v, vlen);		\
 				} else if (clip) {			\
-					if (check_min(um, (t)(min))) {	\
+					if (check_min(mv, (t)(min))) {	\
 						o = (t)(min);		\
 					} else if (			\
-					    check_max(um, (t)(max))) {	\
+					    check_max(mv, (t)(max))) {	\
 						o = (t)(max);		\
 					} else {			\
-						o = (t)um;		\
+						o = (t)mv;		\
 					}				\
 				} else {				\
-					if (check_min(um, (t)(min)) ||	\
+					if (check_min(mv, (t)(min)) ||	\
-					    check_max(um, (t)(max))) {	\
+					    check_max(mv, (t)(max))) {	\
 						CONF_ERROR(		\
 						    "Out-of-range "	\
 						    "conf value",	\
 						    k, klen, v, vlen);	\
 					} else {			\
-						o = (t)um;		\
+						o = (t)mv;		\
 					}				\
 				}					\
 				CONF_CONTINUE;				\
 			}
+#define CONF_HANDLE_T_U(t, o, n, min, max, check_min, check_max, clip)	\
+	      CONF_HANDLE_T(t, uintmax_t, o, n, min, max, check_min,	\
+			    check_max, clip)
+#define CONF_HANDLE_T_SIGNED(t, o, n, min, max, check_min, check_max, clip)\
+	      CONF_HANDLE_T(t, intmax_t, o, n, min, max, check_min,	\
+			    check_max, clip)
+
 #define CONF_HANDLE_UNSIGNED(o, n, min, max, check_min, check_max,	\
     clip)								\
 			CONF_HANDLE_T_U(unsigned, o, n, min, max,	\
@@ -1158,27 +1166,12 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 #define CONF_HANDLE_SIZE_T(o, n, min, max, check_min, check_max, clip)	\
 			CONF_HANDLE_T_U(size_t, o, n, min, max,		\
 			    check_min, check_max, clip)
+#define CONF_HANDLE_INT64_T(o, n, min, max, check_min, check_max, clip)	\
+			CONF_HANDLE_T_SIGNED(int64_t, o, n, min, max,	\
+			    check_min, check_max, clip)
 #define CONF_HANDLE_SSIZE_T(o, n, min, max)				\
-			if (CONF_MATCH(n)) {				\
+			CONF_HANDLE_T_SIGNED(ssize_t, o, n, min, max,	\
-				long l;					\
+			    CONF_CHECK_MIN, CONF_CHECK_MAX, false)
-				char *end;				\
-									\
-				set_errno(0);				\
-				l = strtol(v, &end, 0);			\
-				if (get_errno() != 0 || (uintptr_t)end -\
-				    (uintptr_t)v != vlen) {		\
-					CONF_ERROR("Invalid conf value",\
-					    k, klen, v, vlen);		\
-				} else if (l < (ssize_t)(min) || l >	\
-				    (ssize_t)(max)) {			\
-					CONF_ERROR(			\
-					    "Out-of-range conf value",	\
-					    k, klen, v, vlen);		\
-				} else {				\
-					o = l;				\
-				}					\
-				CONF_CONTINUE;				\
-			}
 #define CONF_HANDLE_CHAR_P(o, n, d)					\
 			if (CONF_MATCH(n)) {				\
 				size_t cpylen = (vlen <=		\
@@ -1275,7 +1268,16 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 			    SSIZE_MAX);
 			CONF_HANDLE_BOOL(opt_stats_print, "stats_print")
 			if (CONF_MATCH("stats_print_opts")) {
-				init_opt_stats_print_opts(v, vlen);
+				init_opt_stats_opts(v, vlen,
+				    opt_stats_print_opts);
+				CONF_CONTINUE;
+			}
+			CONF_HANDLE_INT64_T(opt_stats_interval,
+			    "stats_interval", -1, INT64_MAX,
+			    CONF_CHECK_MIN, CONF_DONT_CHECK_MAX, false)
+			if (CONF_MATCH("stats_interval_opts")) {
+				init_opt_stats_opts(v, vlen,
+				    opt_stats_interval_opts);
 				CONF_CONTINUE;
 			}
 			if (config_fill) {
@@ -1463,7 +1465,9 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 #undef CONF_CHECK_MIN
 #undef CONF_DONT_CHECK_MAX
 #undef CONF_CHECK_MAX
+#undef CONF_HANDLE_T
 #undef CONF_HANDLE_T_U
+#undef CONF_HANDLE_T_SIGNED
 #undef CONF_HANDLE_UNSIGNED
 #undef CONF_HANDLE_SIZE_T
 #undef CONF_HANDLE_SSIZE_T
@@ -1545,7 +1549,6 @@ malloc_init_hard_a0_locked() {
 		prof_boot0();
 	}
 	malloc_conf_init(&sc_data, bin_shard_sizes);
-	thread_event_boot();
 	sz_boot(&sc_data);
 	bin_info_boot(&sc_data, bin_shard_sizes);
 
@@ -1558,6 +1561,10 @@ malloc_init_hard_a0_locked() {
 			}
 		}
 	}
+
+	if (stats_boot()) {
+		return true;
+	}
 	if (pages_boot()) {
 		return true;
 	}
@@ -1573,6 +1580,7 @@ malloc_init_hard_a0_locked() {
 	if (config_prof) {
 		prof_boot1();
 	}
+	thread_event_boot();
 	arena_boot(&sc_data);
 	if (tcache_boot(TSDN_NULL)) {
 		return true;

src/prof.c

@@ -571,7 +571,10 @@ void
 prof_idump_rollback_impl(tsdn_t *tsdn, size_t usize) {
 	cassert(config_prof);
 
-	return counter_rollback(tsdn, &prof_idump_accumulated, usize);
+	/* Rollback is only done on arena_prof_promote of small sizes. */
+	assert(SC_LARGE_MINCLASS > usize);
+	return counter_rollback(tsdn, &prof_idump_accumulated,
+	    SC_LARGE_MINCLASS - usize);
 }
 
 bool

src/stats.c

@@ -50,6 +50,13 @@ const char *arena_mutex_names[mutex_prof_num_arena_mutexes] = {
 bool opt_stats_print = false;
 char opt_stats_print_opts[stats_print_tot_num_options+1] = "";
 
+int64_t opt_stats_interval = STATS_INTERVAL_DEFAULT;
+char opt_stats_interval_opts[stats_print_tot_num_options+1] = "";
+
+static counter_accum_t stats_interval_accumulated;
+/* Per thread batch accum size for stats_interval. */
+static uint64_t stats_interval_accum_batch;
+
 /******************************************************************************/
 
 static uint64_t
@@ -1000,14 +1007,16 @@ stats_general_print(emitter_t *emitter) {
 	unsigned uv;
 	uint32_t u32v;
 	uint64_t u64v;
+	int64_t i64v;
 	ssize_t ssv, ssv2;
-	size_t sv, bsz, usz, ssz, sssz, cpsz;
+	size_t sv, bsz, usz, i64sz, ssz, sssz, cpsz;
 
 	bsz = sizeof(bool);
 	usz = sizeof(unsigned);
 	ssz = sizeof(size_t);
 	sssz = sizeof(ssize_t);
 	cpsz = sizeof(const char *);
+	i64sz = sizeof(int64_t);
 
 	CTL_GET("version", &cpv, const char *);
 	emitter_kv(emitter, "version", "Version", emitter_type_string, &cpv);
@@ -1063,6 +1072,9 @@ stats_general_print(emitter_t *emitter) {
 #define OPT_WRITE_UNSIGNED(name)					\
 	OPT_WRITE(name, uv, usz, emitter_type_unsigned)
 
+#define OPT_WRITE_INT64(name)						\
+	OPT_WRITE(name, i64v, i64sz, emitter_type_int64)
+
 #define OPT_WRITE_SIZE_T(name)						\
 	OPT_WRITE(name, sv, ssz, emitter_type_size)
 #define OPT_WRITE_SSIZE_T(name)						\
@@ -1109,6 +1121,10 @@ stats_general_print(emitter_t *emitter) {
 	OPT_WRITE_BOOL("prof_leak")
 	OPT_WRITE_BOOL("stats_print")
 	OPT_WRITE_CHAR_P("stats_print_opts")
+	OPT_WRITE_BOOL("stats_print")
+	OPT_WRITE_CHAR_P("stats_print_opts")
+	OPT_WRITE_INT64("stats_interval")
+	OPT_WRITE_CHAR_P("stats_interval_opts")
 	OPT_WRITE_CHAR_P("zero_realloc")
 
 	emitter_dict_end(emitter);
@@ -1477,3 +1493,37 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 	emitter_table_printf(&emitter, "--- End jemalloc statistics ---\n");
 	emitter_end(&emitter);
 }
+
+bool
+stats_interval_accum(tsd_t *tsd, uint64_t bytes) {
+	return counter_accum(tsd_tsdn(tsd), &stats_interval_accumulated, bytes);
+}
+
+uint64_t
+stats_interval_accum_batch_size(void) {
+	return stats_interval_accum_batch;
+}
+
+bool
+stats_boot(void) {
+	uint64_t stats_interval;
+	if (opt_stats_interval < 0) {
+		assert(opt_stats_interval == -1);
+		stats_interval = 0;
+		stats_interval_accum_batch = 0;
+	} else{
+		/* See comments in stats.h */
+		stats_interval = (opt_stats_interval > 0) ?
+		    opt_stats_interval : 1;
+		uint64_t batch = stats_interval >>
+		    STATS_INTERVAL_ACCUM_LG_BATCH_SIZE;
+		if (batch > STATS_INTERVAL_ACCUM_BATCH_MAX) {
+			batch = STATS_INTERVAL_ACCUM_BATCH_MAX;
+		} else if (batch == 0) {
+			batch = 1;
+		}
+		stats_interval_accum_batch = batch;
+	}
+
+	return counter_accum_init(&stats_interval_accumulated, stats_interval);
+}

src/thread_event.c

@@ -25,6 +25,7 @@ static void thread_##event##_event_handler(tsd_t *tsd);
 ITERATE_OVER_ALL_EVENTS
 #undef E
 
+/* (Re)Init functions. */
 static void
 tsd_thread_tcache_gc_event_init(tsd_t *tsd) {
 	assert(TCACHE_GC_INCR_BYTES > 0);
@@ -37,11 +38,19 @@ tsd_thread_prof_sample_event_init(tsd_t *tsd) {
 	prof_sample_threshold_update(tsd);
 }
 
+static void
+tsd_thread_stats_interval_event_init(tsd_t *tsd) {
+	assert(opt_stats_interval >= 0);
+	uint64_t interval = stats_interval_accum_batch_size();
+	thread_stats_interval_event_update(tsd, interval);
+}
+
+/* Handler functions. */
 static void
 thread_tcache_gc_event_handler(tsd_t *tsd) {
 	assert(TCACHE_GC_INCR_BYTES > 0);
 	assert(tcache_gc_event_wait_get(tsd) == 0U);
-	thread_tcache_gc_event_update(tsd, TCACHE_GC_INCR_BYTES);
+	tsd_thread_tcache_gc_event_init(tsd);
 	tcache_t *tcache = tcache_get(tsd);
 	if (tcache != NULL) {
 		tcache_event_hard(tsd, tcache);
@@ -71,6 +80,21 @@ thread_prof_sample_event_handler(tsd_t *tsd) {
 	}
 }
 
+static void
+thread_stats_interval_event_handler(tsd_t *tsd) {
+	assert(opt_stats_interval >= 0);
+	assert(stats_interval_event_wait_get(tsd) == 0U);
+	uint64_t last_event = thread_allocated_last_event_get(tsd);
+	uint64_t last_stats_event = stats_interval_last_event_get(tsd);
+	stats_interval_last_event_set(tsd, last_event);
+
+	if (stats_interval_accum(tsd, last_event - last_stats_event)) {
+		je_malloc_stats_print(NULL, NULL, opt_stats_interval_opts);
+	}
+	tsd_thread_stats_interval_event_init(tsd);
+}
+/* Per event facilities done. */
+
 static uint64_t
 thread_allocated_next_event_compute(tsd_t *tsd) {
 	uint64_t wait = THREAD_EVENT_MAX_START_WAIT;

test/unit/counter.c

@@ -0,0 +1,128 @@
+#include "test/jemalloc_test.h"
+
+static const uint64_t interval = 1 << 20;
+
+TEST_BEGIN(test_counter_accum) {
+	uint64_t increment = interval >> 4;
+	unsigned n = interval / increment;
+	uint64_t accum = 0;
+
+	counter_accum_t c;
+	counter_accum_init(&c, interval);
+
+	tsd_t *tsd = tsd_fetch();
+	bool trigger;
+	for (unsigned i = 0; i < n; i++) {
+		trigger = counter_accum(tsd_tsdn(tsd), &c, increment);
+		accum += increment;
+		if (accum < interval) {
+			assert_b_eq(trigger, false, "Should not trigger");
+		} else {
+			assert_b_eq(trigger, true, "Should have triggered");
+		}
+	}
+	assert_b_eq(trigger, true, "Should have triggered");
+}
+TEST_END
+
+void
+assert_counter_value(counter_accum_t *c, uint64_t v) {
+	uint64_t accum;
+#ifdef JEMALLOC_ATOMIC_U64
+	accum = atomic_load_u64(&(c->accumbytes), ATOMIC_RELAXED);
+#else
+	accum = c->accumbytes;
+#endif
+	assert_u64_eq(accum, v, "Counter value mismatch");
+}
+
+TEST_BEGIN(test_counter_rollback) {
+	uint64_t half_interval = interval / 2;
+
+	counter_accum_t c;
+	counter_accum_init(&c, interval);
+
+	tsd_t *tsd = tsd_fetch();
+	counter_rollback(tsd_tsdn(tsd), &c, half_interval);
+
+	bool trigger;
+	trigger = counter_accum(tsd_tsdn(tsd), &c, half_interval);
+	assert_b_eq(trigger, false, "Should not trigger");
+	counter_rollback(tsd_tsdn(tsd), &c, half_interval + 1);
+	assert_counter_value(&c,  0);
+
+	trigger = counter_accum(tsd_tsdn(tsd), &c, half_interval);
+	assert_b_eq(trigger, false, "Should not trigger");
+	counter_rollback(tsd_tsdn(tsd), &c, half_interval - 1);
+	assert_counter_value(&c,  1);
+
+	counter_rollback(tsd_tsdn(tsd), &c, 1);
+	assert_counter_value(&c,  0);
+
+	trigger = counter_accum(tsd_tsdn(tsd), &c, half_interval);
+	assert_b_eq(trigger, false, "Should not trigger");
+	counter_rollback(tsd_tsdn(tsd), &c, 1);
+	assert_counter_value(&c,  half_interval - 1);
+
+	trigger = counter_accum(tsd_tsdn(tsd), &c, half_interval);
+	assert_b_eq(trigger, false, "Should not trigger");
+	assert_counter_value(&c,  interval - 1);
+
+	trigger = counter_accum(tsd_tsdn(tsd), &c, 1);
+	assert_b_eq(trigger, true, "Should have triggered");
+	assert_counter_value(&c, 0);
+
+	trigger = counter_accum(tsd_tsdn(tsd), &c, interval + 1);
+	assert_b_eq(trigger, true, "Should have triggered");
+	assert_counter_value(&c, 1);
+}
+TEST_END
+
+#define N_THDS (16)
+#define N_ITER_THD (1 << 12)
+#define ITER_INCREMENT (interval >> 4)
+
+static void *
+thd_start(void *varg) {
+	counter_accum_t *c = (counter_accum_t *)varg;
+
+	tsd_t *tsd = tsd_fetch();
+	bool trigger;
+	uintptr_t n_triggered = 0;
+	for (unsigned i = 0; i < N_ITER_THD; i++) {
+		trigger = counter_accum(tsd_tsdn(tsd), c, ITER_INCREMENT);
+		n_triggered += trigger ? 1 : 0;
+	}
+
+	return (void *)n_triggered;
+}
+
+
+TEST_BEGIN(test_counter_mt) {
+	counter_accum_t shared_c;
+	counter_accum_init(&shared_c, interval);
+
+	thd_t thds[N_THDS];
+	unsigned i;
+	for (i = 0; i < N_THDS; i++) {
+		thd_create(&thds[i], thd_start, (void *)&shared_c);
+	}
+
+	uint64_t sum = 0;
+	for (i = 0; i < N_THDS; i++) {
+		void *ret;
+		thd_join(thds[i], &ret);
+		sum += (uintptr_t)ret;
+	}
+	assert_u64_eq(sum, N_THDS * N_ITER_THD / (interval / ITER_INCREMENT),
+	    "Incorrect number of triggers");
+}
+TEST_END
+
+int
+main(void) {
+	return test(
+	    test_counter_accum,
+	    test_counter_rollback,
+	    test_counter_mt);
+}

test/unit/mallctl.c

@@ -170,6 +170,9 @@ TEST_BEGIN(test_mallctl_opt) {
 	TEST_MALLCTL_OPT(ssize_t, dirty_decay_ms, always);
 	TEST_MALLCTL_OPT(ssize_t, muzzy_decay_ms, always);
 	TEST_MALLCTL_OPT(bool, stats_print, always);
+	TEST_MALLCTL_OPT(const char *, stats_print_opts, always);
+	TEST_MALLCTL_OPT(int64_t, stats_interval, always);
+	TEST_MALLCTL_OPT(const char *, stats_interval_opts, always);
 	TEST_MALLCTL_OPT(const char *, junk, fill);
 	TEST_MALLCTL_OPT(bool, zero, fill);
 	TEST_MALLCTL_OPT(bool, utrace, utrace);