/* * * Copyright 2015 gRPC authors. * * 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. * */ /* Test of gpr synchronization support. */ #include #include #include "gtest/gtest.h" #include #include #include #include #include "src/core/lib/gprpp/thd.h" #include "test/core/util/test_config.h" /* ==================Example use of interface=================== A producer-consumer queue of up to N integers, illustrating the use of the calls in this interface. */ #define N 4 typedef struct queue { gpr_cv non_empty; /* Signalled when length becomes non-zero. */ gpr_cv non_full; /* Signalled when length becomes non-N. */ gpr_mu mu; /* Protects all fields below. (That is, except during initialization or destruction, the fields below should be accessed only by a thread that holds mu.) */ int head; /* Index of head of queue 0..N-1. */ int length; /* Number of valid elements in queue 0..N. */ int elem[N]; /* elem[head .. head+length-1] are queue elements. */ } queue; /* Initialize *q. */ void queue_init(queue* q) { gpr_mu_init(&q->mu); gpr_cv_init(&q->non_empty); gpr_cv_init(&q->non_full); q->head = 0; q->length = 0; } /* Free storage associated with *q. */ void queue_destroy(queue* q) { gpr_mu_destroy(&q->mu); gpr_cv_destroy(&q->non_empty); gpr_cv_destroy(&q->non_full); } /* Wait until there is room in *q, then append x to *q. */ void queue_append(queue* q, int x) { gpr_mu_lock(&q->mu); /* To wait for a predicate without a deadline, loop on the negation of the predicate, and use gpr_cv_wait(..., gpr_inf_future(GPR_CLOCK_REALTIME)) inside the loop to release the lock, wait, and reacquire on each iteration. Code that makes the condition true should use gpr_cv_broadcast() on the corresponding condition variable. The predicate must be on state protected by the lock. */ while (q->length == N) { gpr_cv_wait(&q->non_full, &q->mu, gpr_inf_future(GPR_CLOCK_MONOTONIC)); } if (q->length == 0) { /* Wake threads blocked in queue_remove(). */ /* It's normal to use gpr_cv_broadcast() or gpr_signal() while holding the lock. */ gpr_cv_broadcast(&q->non_empty); } q->elem[(q->head + q->length) % N] = x; q->length++; gpr_mu_unlock(&q->mu); } /* If it can be done without blocking, append x to *q and return non-zero. Otherwise return 0. */ int queue_try_append(queue* q, int x) { int result = 0; if (gpr_mu_trylock(&q->mu)) { if (q->length != N) { if (q->length == 0) { /* Wake threads blocked in queue_remove(). */ gpr_cv_broadcast(&q->non_empty); } q->elem[(q->head + q->length) % N] = x; q->length++; result = 1; } gpr_mu_unlock(&q->mu); } return result; } /* Wait until the *q is non-empty or deadline abs_deadline passes. If the queue is non-empty, remove its head entry, place it in *head, and return non-zero. Otherwise return 0. */ int queue_remove(queue* q, int* head, gpr_timespec abs_deadline) { int result = 0; gpr_mu_lock(&q->mu); /* To wait for a predicate with a deadline, loop on the negation of the predicate or until gpr_cv_wait() returns true. Code that makes the condition true should use gpr_cv_broadcast() on the corresponding condition variable. The predicate must be on state protected by the lock. */ while (q->length == 0 && !gpr_cv_wait(&q->non_empty, &q->mu, abs_deadline)) { } if (q->length != 0) { /* Queue is non-empty. */ result = 1; if (q->length == N) { /* Wake threads blocked in queue_append(). */ gpr_cv_broadcast(&q->non_full); } *head = q->elem[q->head]; q->head = (q->head + 1) % N; q->length--; } /* else deadline exceeded */ gpr_mu_unlock(&q->mu); return result; } /* ------------------------------------------------- */ /* Tests for gpr_mu and gpr_cv, and the queue example. */ struct test { int nthreads; /* number of threads */ grpc_core::Thread* threads; int64_t iterations; /* number of iterations per thread */ int64_t counter; int thread_count; /* used to allocate thread ids */ int done; /* threads not yet completed */ int incr_step; /* how much to increment/decrement refcount each time */ gpr_mu mu; /* protects iterations, counter, thread_count, done */ gpr_cv cv; /* signalling depends on test */ gpr_cv done_cv; /* signalled when done == 0 */ queue q; gpr_stats_counter stats_counter; gpr_refcount refcount; gpr_refcount thread_refcount; gpr_event event; }; /* Return pointer to a new struct test. */ static struct test* test_new(int nthreads, int64_t iterations, int incr_step) { struct test* m = static_cast(gpr_malloc(sizeof(*m))); m->nthreads = nthreads; m->threads = static_cast( gpr_malloc(sizeof(*m->threads) * nthreads)); m->iterations = iterations; m->counter = 0; m->thread_count = 0; m->done = nthreads; m->incr_step = incr_step; gpr_mu_init(&m->mu); gpr_cv_init(&m->cv); gpr_cv_init(&m->done_cv); queue_init(&m->q); gpr_stats_init(&m->stats_counter, 0); gpr_ref_init(&m->refcount, 0); gpr_ref_init(&m->thread_refcount, nthreads); gpr_event_init(&m->event); return m; } /* Return pointer to a new struct test. */ static void test_destroy(struct test* m) { gpr_mu_destroy(&m->mu); gpr_cv_destroy(&m->cv); gpr_cv_destroy(&m->done_cv); queue_destroy(&m->q); gpr_free(m->threads); gpr_free(m); } /* Create m->nthreads threads, each running (*body)(m) */ static void test_create_threads(struct test* m, void (*body)(void* arg)) { int i; for (i = 0; i != m->nthreads; i++) { m->threads[i] = grpc_core::Thread("grpc_create_threads", body, m); m->threads[i].Start(); } } /* Wait until all threads report done. */ static void test_wait(struct test* m) { gpr_mu_lock(&m->mu); while (m->done != 0) { gpr_cv_wait(&m->done_cv, &m->mu, gpr_inf_future(GPR_CLOCK_MONOTONIC)); } gpr_mu_unlock(&m->mu); for (int i = 0; i != m->nthreads; i++) { m->threads[i].Join(); } } /* Get an integer thread id in the raneg 0..nthreads-1 */ static int thread_id(struct test* m) { int id; gpr_mu_lock(&m->mu); id = m->thread_count++; gpr_mu_unlock(&m->mu); return id; } /* Indicate that a thread is done, by decrementing m->done and signalling done_cv if m->done==0. */ static void mark_thread_done(struct test* m) { gpr_mu_lock(&m->mu); ASSERT_NE(m->done, 0); m->done--; if (m->done == 0) { gpr_cv_signal(&m->done_cv); } gpr_mu_unlock(&m->mu); } /* Test several threads running (*body)(struct test *m) for increasing settings of m->iterations, until about timeout_s to 2*timeout_s seconds have elapsed. If extra!=NULL, run (*extra)(m) in an additional thread. incr_step controls by how much m->refcount should be incremented/decremented (if at all) each time in the tests. */ static void test(const char* name, void (*body)(void* m), void (*extra)(void* m), int timeout_s, int incr_step) { int64_t iterations = 8; struct test* m; gpr_timespec start = gpr_now(GPR_CLOCK_REALTIME); gpr_timespec time_taken; gpr_timespec deadline = gpr_time_add( start, gpr_time_from_micros(static_cast(timeout_s) * 1000000, GPR_TIMESPAN)); fprintf(stderr, "%s:", name); fflush(stderr); while (gpr_time_cmp(gpr_now(GPR_CLOCK_REALTIME), deadline) < 0) { fprintf(stderr, " %ld", static_cast(iterations)); fflush(stderr); m = test_new(10, iterations, incr_step); grpc_core::Thread extra_thd; if (extra != nullptr) { extra_thd = grpc_core::Thread(name, extra, m); extra_thd.Start(); m->done++; /* one more thread to wait for */ } test_create_threads(m, body); test_wait(m); if (extra != nullptr) { extra_thd.Join(); } if (m->counter != m->nthreads * m->iterations * m->incr_step) { fprintf(stderr, "counter %ld threads %d iterations %ld\n", static_cast(m->counter), m->nthreads, static_cast(m->iterations)); fflush(stderr); ASSERT_TRUE(0); } test_destroy(m); iterations <<= 1; } time_taken = gpr_time_sub(gpr_now(GPR_CLOCK_REALTIME), start); fprintf(stderr, " done %lld.%09d s\n", static_cast(time_taken.tv_sec), static_cast(time_taken.tv_nsec)); fflush(stderr); } /* Increment m->counter on each iteration; then mark thread as done. */ static void inc(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; for (i = 0; i != m->iterations; i++) { gpr_mu_lock(&m->mu); m->counter++; gpr_mu_unlock(&m->mu); } mark_thread_done(m); } /* Increment m->counter under lock acquired with trylock, m->iterations times; then mark thread as done. */ static void inctry(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; for (i = 0; i != m->iterations;) { if (gpr_mu_trylock(&m->mu)) { m->counter++; gpr_mu_unlock(&m->mu); i++; } } mark_thread_done(m); } /* Increment counter only when (m->counter%m->nthreads)==m->thread_id; then mark thread as done. */ static void inc_by_turns(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; int id = thread_id(m); for (i = 0; i != m->iterations; i++) { gpr_mu_lock(&m->mu); while ((m->counter % m->nthreads) != id) { gpr_cv_wait(&m->cv, &m->mu, gpr_inf_future(GPR_CLOCK_MONOTONIC)); } m->counter++; gpr_cv_broadcast(&m->cv); gpr_mu_unlock(&m->mu); } mark_thread_done(m); } /* Wait a millisecond and increment counter on each iteration; then mark thread as done. */ static void inc_with_1ms_delay(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; for (i = 0; i != m->iterations; i++) { gpr_timespec deadline; gpr_mu_lock(&m->mu); deadline = gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_micros(1000, GPR_TIMESPAN)); while (!gpr_cv_wait(&m->cv, &m->mu, deadline)) { } m->counter++; gpr_mu_unlock(&m->mu); } mark_thread_done(m); } /* Wait a millisecond and increment counter on each iteration, using an event for timing; then mark thread as done. */ static void inc_with_1ms_delay_event(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; for (i = 0; i != m->iterations; i++) { gpr_timespec deadline; deadline = gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_micros(1000, GPR_TIMESPAN)); ASSERT_EQ(gpr_event_wait(&m->event, deadline), nullptr); gpr_mu_lock(&m->mu); m->counter++; gpr_mu_unlock(&m->mu); } mark_thread_done(m); } /* Produce m->iterations elements on queue m->q, then mark thread as done. Even threads use queue_append(), and odd threads use queue_try_append() until it succeeds. */ static void many_producers(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; int x = thread_id(m); if ((x & 1) == 0) { for (i = 0; i != m->iterations; i++) { queue_append(&m->q, 1); } } else { for (i = 0; i != m->iterations; i++) { while (!queue_try_append(&m->q, 1)) { } } } mark_thread_done(m); } /* Consume elements from m->q until m->nthreads*m->iterations are seen, wait an extra second to confirm that no more elements are arriving, then mark thread as done. */ static void consumer(void* v /*=m*/) { struct test* m = static_cast(v); int64_t n = m->iterations * m->nthreads; int64_t i; int value; for (i = 0; i != n; i++) { queue_remove(&m->q, &value, gpr_inf_future(GPR_CLOCK_MONOTONIC)); } gpr_mu_lock(&m->mu); m->counter = n; gpr_mu_unlock(&m->mu); ASSERT_TRUE( !queue_remove(&m->q, &value, gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_micros(1000000, GPR_TIMESPAN)))); mark_thread_done(m); } /* Increment m->stats_counter m->iterations times, transfer counter value to m->counter, then mark thread as done. */ static void statsinc(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; for (i = 0; i != m->iterations; i++) { gpr_stats_inc(&m->stats_counter, 1); } gpr_mu_lock(&m->mu); m->counter = gpr_stats_read(&m->stats_counter); gpr_mu_unlock(&m->mu); mark_thread_done(m); } /* Increment m->refcount by m->incr_step for m->iterations times. Decrement m->thread_refcount once, and if it reaches zero, set m->event to (void*)1; then mark thread as done. */ static void refinc(void* v /*=m*/) { struct test* m = static_cast(v); int64_t i; for (i = 0; i != m->iterations; i++) { if (m->incr_step == 1) { gpr_ref(&m->refcount); } else { gpr_refn(&m->refcount, m->incr_step); } } if (gpr_unref(&m->thread_refcount)) { gpr_event_set(&m->event, reinterpret_cast(1)); } mark_thread_done(m); } /* Wait until m->event is set to (void *)1, then decrement m->refcount by 1 (m->nthreads * m->iterations * m->incr_step) times, and ensure that the last decrement caused the counter to reach zero, then mark thread as done. */ static void refcheck(void* v /*=m*/) { struct test* m = static_cast(v); int64_t n = m->iterations * m->nthreads * m->incr_step; int64_t i; ASSERT_EQ(gpr_event_wait(&m->event, gpr_inf_future(GPR_CLOCK_REALTIME)), (void*)1); ASSERT_EQ(gpr_event_get(&m->event), (void*)1); for (i = 1; i != n; i++) { ASSERT_FALSE(gpr_unref(&m->refcount)); m->counter++; } ASSERT_TRUE(gpr_unref(&m->refcount)); m->counter++; mark_thread_done(m); } /* ------------------------------------------------- */ TEST(SyncTest, MainTest) { test("mutex", &inc, nullptr, 1, 1); test("mutex try", &inctry, nullptr, 1, 1); test("cv", &inc_by_turns, nullptr, 1, 1); test("timedcv", &inc_with_1ms_delay, nullptr, 1, 1); test("queue", &many_producers, &consumer, 10, 1); test("stats_counter", &statsinc, nullptr, 1, 1); test("refcount by 1", &refinc, &refcheck, 1, 1); test("refcount by 3", &refinc, &refcheck, 1, 3); /* incr_step of 3 is an arbitrary choice. Any number > 1 is okay here */ test("timedevent", &inc_with_1ms_delay_event, nullptr, 1, 1); } int main(int argc, char** argv) { grpc::testing::TestEnvironment env(&argc, argv); ::testing::InitGoogleTest(&argc, argv); return RUN_ALL_TESTS(); }