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/*
*
* 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;
}
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