*/
#define _GNU_SOURCE
+#include "../config.h"
#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <assert.h>
#include <sched.h>
#include <errno.h>
+#include <signal.h>
#ifdef __linux__
#include <syscall.h>
#endif
#define DEFAULT_HASH_SIZE 32
+#define DEFAULT_MIN_ALLOC_SIZE 1
#define DEFAULT_RAND_POOL 1000000
+/*
+ * Note: the hash seed should be a random value for hash tables
+ * targeting production environments to provide protection against
+ * denial of service attacks. We keep it a static value within this test
+ * program to compare identical benchmark runs.
+ */
+#define TEST_HASH_SEED 0x42UL
+
/* Make this big enough to include the POWER5+ L3 cacheline size of 256B */
#define CACHE_LINE_SIZE 4096
int b;
};
+struct lfht_test_node {
+ struct cds_lfht_node node;
+ void *key;
+ unsigned int key_len;
+ /* cache-cold for iteration */
+ struct rcu_head head;
+};
+
+static inline struct lfht_test_node *
+to_test_node(struct cds_lfht_node *node)
+{
+ return caa_container_of(node, struct lfht_test_node, node);
+}
+
+static inline
+void lfht_test_node_init(struct lfht_test_node *node, void *key,
+ size_t key_len)
+{
+ cds_lfht_node_init(&node->node);
+ node->key = key;
+ node->key_len = key_len;
+}
+
+static inline struct lfht_test_node *
+cds_lfht_iter_get_test_node(struct cds_lfht_iter *iter)
+{
+ return to_test_node(cds_lfht_iter_get_node(iter));
+}
+
static volatile int test_go, test_stop;
static unsigned long wdelay;
static unsigned long rduration;
static unsigned long init_hash_size = DEFAULT_HASH_SIZE;
+static unsigned long min_hash_alloc_size = DEFAULT_MIN_ALLOC_SIZE;
+static unsigned long max_hash_buckets_size = (1UL << 20);
static unsigned long init_populate;
static int opt_auto_resize;
-static int add_only, add_unique;
+static int add_only, add_unique, add_replace;
+static const struct cds_lfht_mm_type *memory_backend;
static unsigned long init_pool_offset, lookup_pool_offset, write_pool_offset;
static unsigned long init_pool_size = DEFAULT_RAND_POOL,
write_pool_size = DEFAULT_RAND_POOL;
static int validate_lookup;
+static int count_pipe[2];
+
static inline void loop_sleep(unsigned long l)
{
while(l-- != 0)
pthread_mutex_t affinity_mutex = PTHREAD_MUTEX_INITIALIZER;
+#ifndef HAVE_CPU_SET_T
+typedef unsigned long cpu_set_t;
+# define CPU_ZERO(cpuset) do { *(cpuset) = 0; } while(0)
+# define CPU_SET(cpu, cpuset) do { *(cpuset) |= (1UL << (cpu)); } while(0)
+#endif
+
static void set_affinity(void)
{
cpu_set_t mask;
if (!use_affinity)
return;
+#if HAVE_SCHED_SETAFFINITY
ret = pthread_mutex_lock(&affinity_mutex);
if (ret) {
perror("Error in pthread mutex lock");
}
CPU_ZERO(&mask);
CPU_SET(cpu, &mask);
- sched_setaffinity(0, sizeof(mask), &mask);
+#if SCHED_SETAFFINITY_ARGS == 2
+ sched_setaffinity(0, &mask);
+#else
+ sched_setaffinity(0, sizeof(mask), &mask);
+#endif
+#endif /* HAVE_SCHED_SETAFFINITY */
}
static enum {
}
}
+static
+void sigusr2_handler(int signo)
+{
+ char msg[1] = { 0x42 };
+ ssize_t ret;
+
+ do {
+ ret = write(count_pipe[1], msg, 1); /* wakeup thread */
+ } while (ret == -1L && errno == EINTR);
+}
+
/*
* returns 0 if test should end.
*/
#if (CAA_BITS_PER_LONG == 32)
static
-unsigned long test_hash(void *_key, size_t length, unsigned long seed)
+unsigned long test_hash(const void *_key, size_t length, unsigned long seed)
{
- unsigned long key = (unsigned long) _key;
- unsigned long v;
+ unsigned int key = (unsigned int) _key;
- assert(length == sizeof(unsigned long));
- return hash_u32(&v, 1, seed);
+ assert(length == sizeof(unsigned int));
+ return hash_u32(&key, 1, seed);
}
#else
static
-unsigned long test_hash(void *_key, size_t length, unsigned long seed)
+unsigned long test_hash(const void *_key, size_t length, unsigned long seed)
{
union {
uint64_t v64;
#endif
static
-unsigned long test_compare(void *key1, size_t key1_len,
- void *key2, size_t key2_len)
+unsigned long test_compare(const void *key1, size_t key1_len,
+ const void *key2, size_t key2_len)
{
- if (unlikely(key1_len != key2_len))
+ if (caa_unlikely(key1_len != key2_len))
return -1;
assert(key1_len == sizeof(unsigned long));
if (key1 == key2)
return 1;
}
+static
+int test_match(struct cds_lfht_node *node, const void *key)
+{
+ struct lfht_test_node *test_node = to_test_node(node);
+
+ return !test_compare(test_node->key, test_node->key_len,
+ key, sizeof(unsigned long));
+}
+
+static inline
+void cds_lfht_test_lookup(struct cds_lfht *ht, void *key, size_t key_len,
+ struct cds_lfht_iter *iter)
+{
+ assert(key_len == sizeof(unsigned long));
+
+ cds_lfht_lookup(ht, test_hash(key, key_len, TEST_HASH_SEED),
+ test_match, key, iter);
+}
+
+void *thr_count(void *arg)
+{
+ printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
+ "counter", pthread_self(), (unsigned long)gettid());
+
+ rcu_register_thread();
+
+ for (;;) {
+ unsigned long count;
+ long approx_before, approx_after;
+ ssize_t len;
+ char buf[1];
+
+ rcu_thread_offline();
+ len = read(count_pipe[0], buf, 1);
+ rcu_thread_online();
+ if (caa_unlikely(!test_duration_read()))
+ break;
+ if (len != 1)
+ continue;
+ /* Accounting */
+ printf("Counting nodes... ");
+ fflush(stdout);
+ rcu_read_lock();
+ cds_lfht_count_nodes(test_ht, &approx_before, &count,
+ &approx_after);
+ rcu_read_unlock();
+ printf("done.\n");
+ printf("Approximation before node accounting: %ld nodes.\n",
+ approx_before);
+ printf("Accounting of nodes in the hash table: "
+ "%lu nodes.\n",
+ count);
+ printf("Approximation after node accounting: %ld nodes.\n",
+ approx_after);
+ }
+ rcu_unregister_thread();
+ return NULL;
+}
+
void *thr_reader(void *_count)
{
unsigned long long *count = _count;
- struct cds_lfht_node *node;
+ struct lfht_test_node *node;
+ struct cds_lfht_iter iter;
printf_verbose("thread_begin %s, thread id : %lx, tid %lu\n",
"reader", pthread_self(), (unsigned long)gettid());
for (;;) {
rcu_read_lock();
- node = cds_lfht_lookup(test_ht,
+ cds_lfht_test_lookup(test_ht,
(void *)(((unsigned long) rand_r(&rand_lookup) % lookup_pool_size) + lookup_pool_offset),
- sizeof(void *));
+ sizeof(void *), &iter);
+ node = cds_lfht_iter_get_test_node(&iter);
if (node == NULL) {
if (validate_lookup) {
printf("[ERROR] Lookup cannot find initial node.\n");
lookup_ok++;
}
debug_yield_read();
- if (unlikely(rduration))
+ if (caa_unlikely(rduration))
loop_sleep(rduration);
rcu_read_unlock();
nr_reads++;
- if (unlikely(!test_duration_read()))
+ if (caa_unlikely(!test_duration_read()))
break;
- if (unlikely((nr_reads & ((1 << 10) - 1)) == 0))
+ if (caa_unlikely((nr_reads & ((1 << 10) - 1)) == 0))
rcu_quiescent_state();
}
static
void free_node_cb(struct rcu_head *head)
{
- struct cds_lfht_node *node =
- caa_container_of(head, struct cds_lfht_node, head);
+ struct lfht_test_node *node =
+ caa_container_of(head, struct lfht_test_node, head);
free(node);
}
void *thr_writer(void *_count)
{
- struct cds_lfht_node *node, *ret_node;
+ struct lfht_test_node *node;
+ struct cds_lfht_node *ret_node;
+ struct cds_lfht_iter iter;
struct wr_count *count = _count;
int ret;
for (;;) {
if ((addremove == AR_ADD || add_only)
|| (addremove == AR_RANDOM && rand_r(&rand_lookup) & 1)) {
- node = malloc(sizeof(struct cds_lfht_node));
- rcu_read_lock();
- cds_lfht_node_init(node,
+ node = malloc(sizeof(struct lfht_test_node));
+ lfht_test_node_init(node,
(void *)(((unsigned long) rand_r(&rand_lookup) % write_pool_size) + write_pool_offset),
sizeof(void *));
- if (add_unique)
- ret_node = cds_lfht_add_unique(test_ht, node);
- else
- cds_lfht_add(test_ht, node);
+ rcu_read_lock();
+ if (add_unique) {
+ ret_node = cds_lfht_add_unique(test_ht,
+ test_hash(node->key, node->key_len, TEST_HASH_SEED),
+ test_match, node->key, &node->node);
+ } else {
+ if (add_replace)
+ ret_node = cds_lfht_add_replace(test_ht,
+ test_hash(node->key, node->key_len, TEST_HASH_SEED),
+ test_match, node->key, &node->node);
+ else
+ cds_lfht_add(test_ht,
+ test_hash(node->key, node->key_len, TEST_HASH_SEED),
+ &node->node);
+ }
rcu_read_unlock();
- if (add_unique && ret_node != node) {
+ if (add_unique && ret_node != &node->node) {
free(node);
nr_addexist++;
- } else
- nr_add++;
+ } else {
+ if (add_replace && ret_node) {
+ call_rcu(&to_test_node(ret_node)->head,
+ free_node_cb);
+ nr_addexist++;
+ } else {
+ nr_add++;
+ }
+ }
} else {
/* May delete */
rcu_read_lock();
- node = cds_lfht_lookup(test_ht,
+ cds_lfht_test_lookup(test_ht,
(void *)(((unsigned long) rand_r(&rand_lookup) % write_pool_size) + write_pool_offset),
- sizeof(void *));
- if (node)
- ret = cds_lfht_remove(test_ht, node);
- else
- ret = -ENOENT;
+ sizeof(void *), &iter);
+ ret = cds_lfht_del(test_ht, cds_lfht_iter_get_node(&iter));
rcu_read_unlock();
if (ret == 0) {
+ node = cds_lfht_iter_get_test_node(&iter);
call_rcu(&node->head, free_node_cb);
nr_del++;
} else
}
#endif //0
nr_writes++;
- if (unlikely(!test_duration_write()))
+ if (caa_unlikely(!test_duration_write()))
break;
- if (unlikely(wdelay))
+ if (caa_unlikely(wdelay))
loop_sleep(wdelay);
- if (unlikely((nr_writes & ((1 << 10) - 1)) == 0))
+ if (caa_unlikely((nr_writes & ((1 << 10) - 1)) == 0))
rcu_quiescent_state();
}
static int populate_hash(void)
{
- struct cds_lfht_node *node, *ret_node;
+ struct lfht_test_node *node;
+ struct cds_lfht_node *ret_node;
if (!init_populate)
return 0;
- if (add_unique && init_populate * 10 > init_pool_size) {
+ if ((add_unique || add_replace) && init_populate * 10 > init_pool_size) {
printf("WARNING: required to populate %lu nodes (-k), but random "
-"pool is quite small (%lu values) and we are in add_unique (-u) mode. Try with a "
+"pool is quite small (%lu values) and we are in add_unique (-u) or add_replace (-s) mode. Try with a "
"larger random pool (-p option). This may take a while...\n", init_populate, init_pool_size);
}
while (nr_add < init_populate) {
- node = malloc(sizeof(struct cds_lfht_node));
- cds_lfht_node_init(node,
+ node = malloc(sizeof(struct lfht_test_node));
+ lfht_test_node_init(node,
(void *)(((unsigned long) rand_r(&rand_lookup) % init_pool_size) + init_pool_offset),
sizeof(void *));
- if (add_unique)
- ret_node = cds_lfht_add_unique(test_ht, node);
- else
- cds_lfht_add(test_ht, node);
- if (add_unique && ret_node != node) {
+ rcu_read_lock();
+ if (add_unique) {
+ ret_node = cds_lfht_add_unique(test_ht,
+ test_hash(node->key, node->key_len, TEST_HASH_SEED),
+ test_match, node->key, &node->node);
+ } else {
+ if (add_replace)
+ ret_node = cds_lfht_add_replace(test_ht,
+ test_hash(node->key, node->key_len, TEST_HASH_SEED),
+ test_match, node->key, &node->node);
+ else
+ cds_lfht_add(test_ht,
+ test_hash(node->key, node->key_len, TEST_HASH_SEED),
+ &node->node);
+ }
+ rcu_read_unlock();
+ if (add_unique && ret_node != &node->node) {
free(node);
nr_addexist++;
- } else
- nr_add++;
+ } else {
+ if (add_replace && ret_node) {
+ call_rcu(&to_test_node(ret_node)->head, free_node_cb);
+ nr_addexist++;
+ } else {
+ nr_add++;
+ }
+ }
nr_writes++;
}
return 0;
}
+static
+void test_delete_all_nodes(struct cds_lfht *ht)
+{
+ struct cds_lfht_iter iter;
+ struct lfht_test_node *node;
+ unsigned long count = 0;
+
+ cds_lfht_for_each_entry(ht, &iter, node, node) {
+ int ret;
+
+ ret = cds_lfht_del(test_ht, cds_lfht_iter_get_node(&iter));
+ assert(!ret);
+ call_rcu(&node->head, free_node_cb);
+ count++;
+ }
+ printf("deleted %lu nodes.\n", count);
+}
+
void show_usage(int argc, char **argv)
{
- printf("Usage : %s nr_readers nr_writers duration (s)", argv[0]);
+ printf("Usage : %s nr_readers nr_writers duration (s)\n", argv[0]);
#ifdef DEBUG_YIELD
- printf(" [-r] [-w] (yield reader and/or writer)");
+ printf(" [-r] [-w] (yield reader and/or writer)\n");
#endif
- printf(" [-d delay] (writer period (us))");
- printf(" [-c duration] (reader C.S. duration (in loops))");
- printf(" [-v] (verbose output)");
- printf(" [-a cpu#] [-a cpu#]... (affinity)");
- printf(" [-h size] (initial hash table size)");
- printf(" [-u] Uniquify add.");
- printf(" [-i] Add only (no removal).");
- printf(" [-k nr_nodes] Number of nodes to insert initially.");
- printf(" [-A] Automatically resize hash table.");
- printf(" [-R offset] Lookup pool offset.");
- printf(" [-S offset] Write pool offset.");
- printf(" [-T offset] Init pool offset.");
- printf(" [-M size] Lookup pool size.");
- printf(" [-N size] Write pool size.");
- printf(" [-O size] Init pool size.");
- printf(" [-V] Validate lookups of init values (use with filled init pool, same lookup range, with different write range).");
- printf("\n");
+ printf(" [-d delay] (writer period (us))\n");
+ printf(" [-c duration] (reader C.S. duration (in loops))\n");
+ printf(" [-v] (verbose output)\n");
+ printf(" [-a cpu#] [-a cpu#]... (affinity)\n");
+ printf(" [-h size] (initial number of buckets)\n");
+ printf(" [-m size] (minimum number of allocated buckets)\n");
+ printf(" [-n size] (maximum number of buckets)\n");
+ printf(" [not -u nor -s] Add entries (supports redundant keys).\n");
+ printf(" [-u] Uniquify add (no redundant keys).\n");
+ printf(" [-s] Replace (swap) entries.\n");
+ printf(" [-i] Add only (no removal).\n");
+ printf(" [-k nr_nodes] Number of nodes to insert initially.\n");
+ printf(" [-A] Automatically resize hash table.\n");
+ printf(" [-B order|chunk|mmap] Specify the memory backend.\n");
+ printf(" [-R offset] Lookup pool offset.\n");
+ printf(" [-S offset] Write pool offset.\n");
+ printf(" [-T offset] Init pool offset.\n");
+ printf(" [-M size] Lookup pool size.\n");
+ printf(" [-N size] Write pool size.\n");
+ printf(" [-O size] Init pool size.\n");
+ printf(" [-V] Validate lookups of init values (use with filled init pool, same lookup range, with different write range).\n");
+ printf("\n\n");
}
int main(int argc, char **argv)
{
int err;
pthread_t *tid_reader, *tid_writer;
+ pthread_t tid_count;
void *tret;
unsigned long long *count_reader;
struct wr_count *count_writer;
unsigned long long tot_reads = 0, tot_writes = 0,
tot_add = 0, tot_add_exist = 0, tot_remove = 0;
- unsigned long count, removed;
+ unsigned long count;
+ long approx_before, approx_after;
int i, a, ret;
struct sigaction act;
unsigned int remain;
}
init_hash_size = atol(argv[++i]);
break;
+ case 'm':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ return -1;
+ }
+ min_hash_alloc_size = atol(argv[++i]);
+ break;
+ case 'n':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ return -1;
+ }
+ max_hash_buckets_size = atol(argv[++i]);
+ break;
case 'u':
+ if (add_replace) {
+ printf("Please specify at most one of -s or -u.\n");
+ exit(-1);
+ }
add_unique = 1;
break;
+ case 's':
+ if (add_unique) {
+ printf("Please specify at most one of -s or -u.\n");
+ exit(-1);
+ }
+ add_replace = 1;
+ break;
case 'i':
add_only = 1;
break;
case 'A':
opt_auto_resize = 1;
break;
+ case 'B':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ return -1;
+ }
+ i++;
+ if (!strcmp("order", argv[i]))
+ memory_backend = &cds_lfht_mm_order;
+ else if (!strcmp("chunk", argv[i]))
+ memory_backend = &cds_lfht_mm_chunk;
+ else if (!strcmp("mmap", argv[i]))
+ memory_backend = &cds_lfht_mm_mmap;
+ else {
+ printf("Please specify memory backend with order|chunk|mmap.\n");
+ exit(-1);
+ }
+ break;
case 'R':
lookup_pool_offset = atol(argv[++i]);
break;
/* Check if hash size is power of 2 */
if (init_hash_size && init_hash_size & (init_hash_size - 1)) {
- printf("Error: Hash table size %lu is not a power of 2.\n",
+ printf("Error: Initial number of buckets (%lu) is not a power of 2.\n",
init_hash_size);
return -1;
}
+ if (min_hash_alloc_size && min_hash_alloc_size & (min_hash_alloc_size - 1)) {
+ printf("Error: Minimum number of allocated buckets (%lu) is not a power of 2.\n",
+ min_hash_alloc_size);
+ return -1;
+ }
+
+ if (max_hash_buckets_size && max_hash_buckets_size & (max_hash_buckets_size - 1)) {
+ printf("Error: Maximum number of buckets (%lu) is not a power of 2.\n",
+ max_hash_buckets_size);
+ return -1;
+ }
+
memset(&act, 0, sizeof(act));
ret = sigemptyset(&act.sa_mask);
if (ret == -1) {
return -1;
}
+ ret = pipe(count_pipe);
+ if (ret == -1) {
+ perror("pipe");
+ return -1;
+ }
+
+ /* spawn counter thread */
+ err = pthread_create(&tid_count, NULL, thr_count,
+ NULL);
+ if (err != 0)
+ exit(1);
+
+ act.sa_handler = sigusr2_handler;
+ act.sa_flags = SA_RESTART;
+ ret = sigaction(SIGUSR2, &act, NULL);
+ if (ret == -1) {
+ perror("sigaction");
+ return -1;
+ }
+
printf_verbose("running test for %lu seconds, %u readers, %u writers.\n",
duration, nr_readers, nr_writers);
printf_verbose("Writer delay : %lu loops.\n", wdelay);
printf_verbose("Reader duration : %lu loops.\n", rduration);
printf_verbose("Mode:%s%s.\n",
add_only ? " add only" : " add/remove",
- add_unique ? " uniquify" : "");
- printf_verbose("Initial hash table size: %lu buckets.\n", init_hash_size);
+ add_unique ? " uniquify" : ( add_replace ? " replace" : " insert"));
+ printf_verbose("Initial number of buckets: %lu buckets.\n", init_hash_size);
+ printf_verbose("Minimum number of allocated buckets: %lu buckets.\n", min_hash_alloc_size);
+ printf_verbose("Maximum number of buckets: %lu buckets.\n", max_hash_buckets_size);
printf_verbose("Init pool size offset %lu size %lu.\n",
init_pool_offset, init_pool_size);
printf_verbose("Lookup pool size offset %lu size %lu.\n",
tid_writer = malloc(sizeof(*tid_writer) * nr_writers);
count_reader = malloc(sizeof(*count_reader) * nr_readers);
count_writer = malloc(sizeof(*count_writer) * nr_writers);
- test_ht = cds_lfht_new(test_hash, test_compare, 0x42UL,
- init_hash_size,
- opt_auto_resize ? CDS_LFHT_AUTO_RESIZE : 0, NULL);
- ret = populate_hash();
+
+ err = create_all_cpu_call_rcu_data(0);
+ if (err) {
+ printf("Per-CPU call_rcu() worker threads unavailable. Using default global worker thread.\n");
+ }
+
+ if (memory_backend) {
+ test_ht = _cds_lfht_new(init_hash_size, min_hash_alloc_size,
+ max_hash_buckets_size,
+ (opt_auto_resize ? CDS_LFHT_AUTO_RESIZE : 0) |
+ CDS_LFHT_ACCOUNTING, memory_backend,
+ &rcu_flavor, NULL);
+ } else {
+ test_ht = cds_lfht_new(init_hash_size, min_hash_alloc_size,
+ max_hash_buckets_size,
+ (opt_auto_resize ? CDS_LFHT_AUTO_RESIZE : 0) |
+ CDS_LFHT_ACCOUNTING, NULL);
+ }
+
+ /*
+ * Hash Population needs to be seen as a RCU reader
+ * thread from the point of view of resize.
+ */
+ rcu_register_thread();
+ ret = populate_hash();
assert(!ret);
- err = create_all_cpu_call_rcu_data(0);
- assert(!err);
+
+ rcu_thread_offline();
next_aff = 0;
tot_add_exist += count_writer[i].add_exist;
tot_remove += count_writer[i].remove;
}
- printf("Counting nodes... ");
+
+ /* teardown counter thread */
+ act.sa_handler = SIG_IGN;
+ act.sa_flags = SA_RESTART;
+ ret = sigaction(SIGUSR2, &act, NULL);
+ if (ret == -1) {
+ perror("sigaction");
+ return -1;
+ }
+ {
+ char msg[1] = { 0x42 };
+ ssize_t ret;
+
+ do {
+ ret = write(count_pipe[1], msg, 1); /* wakeup thread */
+ } while (ret == -1L && errno == EINTR);
+ }
+ err = pthread_join(tid_count, &tret);
+ if (err != 0)
+ exit(1);
+
fflush(stdout);
- cds_lfht_count_nodes(test_ht, &count, &removed);
+ rcu_thread_online();
+ rcu_read_lock();
+ printf("Counting nodes... ");
+ cds_lfht_count_nodes(test_ht, &approx_before, &count, &approx_after);
printf("done.\n");
- if (count || removed)
- printf("WARNING: nodes left in the hash table upon destroy: "
- "%lu nodes + %lu logically removed.\n", count, removed);
+ test_delete_all_nodes(test_ht);
+ rcu_read_unlock();
+ rcu_thread_offline();
+ if (count) {
+ printf("Approximation before node accounting: %ld nodes.\n",
+ approx_before);
+ printf("Nodes deleted from hash table before destroy: "
+ "%lu nodes.\n",
+ count);
+ printf("Approximation after node accounting: %ld nodes.\n",
+ approx_after);
+ }
ret = cds_lfht_destroy(test_ht, NULL);
-
if (ret)
printf_verbose("final delete aborted\n");
else
nr_writers, wdelay, tot_reads, tot_writes,
tot_reads + tot_writes, tot_add, tot_add_exist, tot_remove,
(long long) tot_add + init_populate - tot_remove - count);
+ rcu_unregister_thread();
free_all_cpu_call_rcu_data();
free(tid_reader);
free(tid_writer);