| /* |
| * |
| * Copyright 2016 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. |
| * |
| */ |
| |
| #include "src/core/lib/support/backoff.h" |
| |
| #include <grpc/support/log.h> |
| |
| #include "test/core/util/test_config.h" |
| |
| static void test_constant_backoff(void) { |
| gpr_backoff backoff; |
| gpr_backoff_init(&backoff, 200 /* initial timeout */, 1.0 /* multiplier */, |
| 0.0 /* jitter */, 100 /* min timeout */, |
| 1000 /* max timeout */); |
| |
| gpr_timespec now = gpr_time_0(GPR_TIMESPAN); |
| gpr_timespec next = gpr_backoff_begin(&backoff, now); |
| GPR_ASSERT(gpr_time_to_millis(gpr_time_sub(next, now)) == 200); |
| for (int i = 0; i < 10000; i++) { |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_to_millis(gpr_time_sub(next, now)) == 200); |
| now = next; |
| } |
| } |
| |
| static void test_min_connect(void) { |
| gpr_backoff backoff; |
| gpr_backoff_init(&backoff, 100 /* initial timeout */, 1.0 /* multiplier */, |
| 0.0 /* jitter */, 200 /* min timeout */, |
| 1000 /* max timeout */); |
| |
| gpr_timespec now = gpr_time_0(GPR_TIMESPAN); |
| gpr_timespec next = gpr_backoff_begin(&backoff, now); |
| GPR_ASSERT(gpr_time_to_millis(gpr_time_sub(next, now)) == 200); |
| } |
| |
| static void test_no_jitter_backoff(void) { |
| gpr_backoff backoff; |
| gpr_backoff_init(&backoff, 2 /* initial timeout */, 2.0 /* multiplier */, |
| 0.0 /* jitter */, 1 /* min timeout */, |
| 513 /* max timeout */); |
| // x_1 = 2 |
| // x_n = 2**i + x_{i-1} ( = 2**(n+1) - 2 ) |
| gpr_timespec now = gpr_time_0(GPR_TIMESPAN); |
| gpr_timespec next = gpr_backoff_begin(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(2, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(6, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(14, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(30, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(62, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(126, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(254, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(510, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(1022, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| // Hit the maximum timeout. From this point onwards, retries will increase |
| // only by max timeout. |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(1535, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(2048, GPR_TIMESPAN), next) == 0); |
| now = next; |
| next = gpr_backoff_step(&backoff, now); |
| GPR_ASSERT(gpr_time_cmp(gpr_time_from_millis(2561, GPR_TIMESPAN), next) == 0); |
| } |
| |
| static void test_jitter_backoff(void) { |
| const int64_t initial_timeout = 500; |
| const double jitter = 0.1; |
| gpr_backoff backoff; |
| gpr_backoff_init(&backoff, initial_timeout, 1.0 /* multiplier */, jitter, |
| 100 /* min timeout */, 1000 /* max timeout */); |
| |
| backoff.rng_state = 0; // force consistent PRNG |
| |
| gpr_timespec now = gpr_time_0(GPR_TIMESPAN); |
| gpr_timespec next = gpr_backoff_begin(&backoff, now); |
| GPR_ASSERT(gpr_time_to_millis(gpr_time_sub(next, now)) == 500); |
| |
| int64_t expected_next_lower_bound = |
| (int64_t)((double)initial_timeout * (1 - jitter)); |
| int64_t expected_next_upper_bound = |
| (int64_t)((double)initial_timeout * (1 + jitter)); |
| |
| for (int i = 0; i < 10000; i++) { |
| next = gpr_backoff_step(&backoff, now); |
| |
| // next-now must be within (jitter*100)% of the previous timeout. |
| const int64_t timeout_millis = gpr_time_to_millis(gpr_time_sub(next, now)); |
| GPR_ASSERT(timeout_millis >= expected_next_lower_bound); |
| GPR_ASSERT(timeout_millis <= expected_next_upper_bound); |
| |
| expected_next_lower_bound = |
| (int64_t)((double)timeout_millis * (1 - jitter)); |
| expected_next_upper_bound = |
| (int64_t)((double)timeout_millis * (1 + jitter)); |
| now = next; |
| } |
| } |
| |
| int main(int argc, char **argv) { |
| grpc_test_init(argc, argv); |
| gpr_time_init(); |
| |
| test_constant_backoff(); |
| test_min_connect(); |
| test_no_jitter_backoff(); |
| test_jitter_backoff(); |
| |
| return 0; |
| } |