/* * * Copyright 2016, Google Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #include "src/core/lib/support/backoff.h" #include #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; }