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authorSverker Eriksson <[email protected]>2019-02-06 19:10:26 +0100
committerSverker Eriksson <[email protected]>2019-02-06 19:10:26 +0100
commit98cfd6016f8b40fc97e03b31177d14318349040f (patch)
treec0fcdd768071c36bfbcbf186d369d9ca14c47421 /erts/emulator/beam/erl_bif_counters.c
parente2ca71b6e7172b320b5b171359d53a161383fb19 (diff)
parent3825199794da28d79b21052a2e69e2335921d55e (diff)
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Merge tag 'OTP-21.2' into sverker/map-from-ks-vs-bug
Diffstat (limited to 'erts/emulator/beam/erl_bif_counters.c')
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1 files changed, 255 insertions, 0 deletions
diff --git a/erts/emulator/beam/erl_bif_counters.c b/erts/emulator/beam/erl_bif_counters.c
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+/*
+ * %CopyrightBegin%
+ *
+ * Copyright Ericsson AB 2018. 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%
+ */
+
+/*
+ * Purpose: The implementation for 'counters' with 'write_concurrency'.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stddef.h> /* offsetof */
+
+#include "sys.h"
+#include "export.h"
+#include "bif.h"
+#include "erl_threads.h"
+#include "big.h"
+#include "erl_binary.h"
+#include "erl_bif_unique.h"
+#include "erl_map.h"
+
+/*
+ * Each logical counter consists of one 64-bit atomic instance per scheduler
+ * plus one instance for the "base value".
+ *
+ * get() reads all atomics for the counter and returns the sum.
+ * add() reads and writes only its own scheduler specific atomic instance.
+ * put() reads all scheduler specific atomics and writes a new base value.
+ */
+#define ATOMICS_PER_COUNTER (erts_no_schedulers + 1)
+
+#define ATOMICS_PER_CACHE_LINE (ERTS_CACHE_LINE_SIZE / sizeof(erts_atomic64_t))
+
+typedef struct
+{
+ UWord arity;
+#ifdef DEBUG
+ UWord ulen;
+#endif
+ union {
+ erts_atomic64_t v[ATOMICS_PER_CACHE_LINE];
+ byte cache_line__[ERTS_CACHE_LINE_SIZE];
+ } u[1];
+}CountersRef;
+
+static int counters_destructor(Binary *mbin)
+{
+ return 1;
+}
+
+
+static UWord ERTS_INLINE div_ceil(UWord dividend, UWord divisor)
+{
+ return (dividend + divisor - 1) / divisor;
+}
+
+BIF_RETTYPE erts_internal_counters_new_1(BIF_ALIST_1)
+{
+ CountersRef* p;
+ Binary* mbin;
+ UWord ui, vi, cnt;
+ Uint bytes, cache_lines;
+ Eterm* hp;
+
+ if (!term_to_UWord(BIF_ARG_1, &cnt)
+ || cnt == 0) {
+ BIF_ERROR(BIF_P, BADARG);
+ }
+
+ if (cnt > (ERTS_UWORD_MAX / (sizeof(erts_atomic64_t)*2*ATOMICS_PER_COUNTER)))
+ BIF_ERROR(BIF_P, SYSTEM_LIMIT);
+
+ cache_lines = ATOMICS_PER_COUNTER * div_ceil(cnt, ATOMICS_PER_CACHE_LINE);
+ bytes = offsetof(CountersRef, u) + cache_lines * ERTS_CACHE_LINE_SIZE;
+ mbin = erts_create_magic_binary_x(bytes,
+ counters_destructor,
+ ERTS_ALC_T_ATOMICS,
+ 0);
+ p = ERTS_MAGIC_BIN_DATA(mbin);
+ p->arity = cnt;
+
+#ifdef DEBUG
+ p->ulen = cache_lines;
+#endif
+ ASSERT((byte*)&p->u[cache_lines] <= ((byte*)p + bytes));
+ for (ui=0; ui < cache_lines; ui++)
+ for (vi=0; vi < ATOMICS_PER_CACHE_LINE; vi++)
+ erts_atomic64_init_nob(&p->u[ui].v[vi], 0);
+ hp = HAlloc(BIF_P, ERTS_MAGIC_REF_THING_SIZE);
+ return erts_mk_magic_ref(&hp, &MSO(BIF_P), mbin);
+}
+
+static ERTS_INLINE int get_ref(Eterm ref, CountersRef** pp)
+{
+ Binary* mbin;
+ if (!is_internal_magic_ref(ref))
+ return 0;
+
+ mbin = erts_magic_ref2bin(ref);
+ if (ERTS_MAGIC_BIN_DESTRUCTOR(mbin) != counters_destructor)
+ return 0;
+ *pp = ERTS_MAGIC_BIN_DATA(mbin);
+ return 1;
+}
+
+static ERTS_INLINE int get_ref_cnt(Eterm ref, Eterm index,
+ CountersRef** pp,
+ erts_atomic64_t** app,
+ UWord sched_ix)
+{
+ CountersRef* p;
+ UWord ix, ui, vi;
+ if (!get_ref(ref, &p) || !term_to_UWord(index, &ix) || --ix >= p->arity)
+ return 0;
+ ui = (ix / ATOMICS_PER_CACHE_LINE) * ATOMICS_PER_COUNTER + sched_ix;
+ vi = ix % ATOMICS_PER_CACHE_LINE;
+ ASSERT(ui < p->ulen);
+ *pp = p;
+ *app = &p->u[ui].v[vi];
+ return 1;
+}
+
+static ERTS_INLINE int get_ref_my_cnt(Eterm ref, Eterm index,
+ CountersRef** pp,
+ erts_atomic64_t** app)
+{
+ ErtsSchedulerData *esdp = erts_get_scheduler_data();
+ ASSERT(esdp && !ERTS_SCHEDULER_IS_DIRTY(esdp));
+ ASSERT(esdp->no > 0 && esdp->no < ATOMICS_PER_COUNTER);
+ return get_ref_cnt(ref, index, pp, app, esdp->no);
+}
+
+static ERTS_INLINE int get_ref_first_cnt(Eterm ref, Eterm index,
+ CountersRef** pp,
+ erts_atomic64_t** app)
+{
+ return get_ref_cnt(ref, index, pp, app, 0);
+}
+
+static ERTS_INLINE int get_incr(CountersRef* p, Eterm term, erts_aint64_t *valp)
+{
+ return (term_to_Sint64(term, (Sint64*)valp)
+ || term_to_Uint64(term, (Uint64*)valp));
+}
+
+static ERTS_INLINE Eterm bld_counter(Process* proc, CountersRef* p,
+ erts_aint64_t val)
+{
+ if (IS_SSMALL(val))
+ return make_small((Sint) val);
+ else {
+ Uint hsz = ERTS_SINT64_HEAP_SIZE(val);
+ Eterm* hp = HAlloc(proc, hsz);
+ return erts_sint64_to_big(val, &hp);
+ }
+}
+
+BIF_RETTYPE erts_internal_counters_get_2(BIF_ALIST_2)
+{
+ CountersRef* p;
+ erts_atomic64_t* ap;
+ erts_aint64_t acc = 0;
+ int j;
+
+ if (!get_ref_first_cnt(BIF_ARG_1, BIF_ARG_2, &p, &ap)) {
+ BIF_ERROR(BIF_P, BADARG);
+ }
+ for (j = ATOMICS_PER_COUNTER; j ; --j) {
+ acc += erts_atomic64_read_nob(ap);
+ ap = (erts_atomic64_t*) ((byte*)ap + ERTS_CACHE_LINE_SIZE);
+ }
+ return bld_counter(BIF_P, p, acc);
+}
+
+BIF_RETTYPE erts_internal_counters_add_3(BIF_ALIST_3)
+{
+ CountersRef* p;
+ erts_atomic64_t* ap;
+ erts_aint64_t incr, sum;
+
+ if (!get_ref_my_cnt(BIF_ARG_1, BIF_ARG_2, &p, &ap)
+ || !get_incr(p, BIF_ARG_3, &incr)) {
+ BIF_ERROR(BIF_P, BADARG);
+ }
+ sum = incr + erts_atomic64_read_nob(ap);
+ erts_atomic64_set_nob(ap, sum);
+ return am_ok;
+}
+
+BIF_RETTYPE erts_internal_counters_put_3(BIF_ALIST_3)
+{
+ CountersRef* p;
+ erts_atomic64_t* first_ap;
+ erts_atomic64_t* ap;
+ erts_aint64_t acc;
+ erts_aint64_t val;
+ int j;
+
+ if (!get_ref_first_cnt(BIF_ARG_1, BIF_ARG_2, &p, &first_ap)
+ || !term_to_Sint64(BIF_ARG_3, &val)) {
+ BIF_ERROR(BIF_P, BADARG);
+ }
+
+ ap = first_ap;
+ acc = 0;
+ j = ATOMICS_PER_COUNTER - 1;
+ do {
+ ap = (erts_atomic64_t*) ((byte*)ap + ERTS_CACHE_LINE_SIZE);
+ acc += erts_atomic64_read_nob(ap);
+ } while (--j);
+ erts_atomic64_set_nob(first_ap, val-acc);
+
+ return am_ok;
+}
+
+BIF_RETTYPE erts_internal_counters_info_1(BIF_ALIST_1)
+{
+ CountersRef* p;
+ Uint hsz = MAP2_SZ;
+ Eterm *hp;
+ UWord memory;
+ Eterm sz_val, mem_val;
+
+ if (!get_ref(BIF_ARG_1, &p))
+ BIF_ERROR(BIF_P, BADARG);
+
+ memory = erts_magic_ref2bin(BIF_ARG_1)->orig_size;
+ erts_bld_uword(NULL, &hsz, p->arity);
+ erts_bld_uword(NULL, &hsz, memory);
+
+ hp = HAlloc(BIF_P, hsz);
+ sz_val = erts_bld_uword(&hp, NULL, p->arity);
+ mem_val = erts_bld_uword(&hp, NULL, memory);
+
+ return MAP2(hp, am_memory, mem_val,
+ am_size, sz_val);
+}