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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/backoff/backoff.h"
#include <grpc/support/log.h>
#include <grpc/support/useful.h>
#include "test/core/util/test_config.h"
static void test_constant_backoff(void) {
grpc_backoff backoff;
const grpc_millis initial_backoff = 200;
const double multiplier = 1.0;
const double jitter = 0.0;
const grpc_millis min_connect_timeout = 100;
const grpc_millis max_backoff = 1000;
grpc_backoff_init(&backoff, initial_backoff, multiplier, jitter,
min_connect_timeout, max_backoff);
grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
grpc_backoff_result next_deadlines = grpc_backoff_begin(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline - grpc_exec_ctx_now(&exec_ctx) ==
initial_backoff);
GPR_ASSERT(next_deadlines.next_attempt_start_time -
grpc_exec_ctx_now(&exec_ctx) ==
initial_backoff);
for (int i = 0; i < 10000; i++) {
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline - grpc_exec_ctx_now(&exec_ctx) ==
initial_backoff);
GPR_ASSERT(next_deadlines.next_attempt_start_time -
grpc_exec_ctx_now(&exec_ctx) ==
initial_backoff);
exec_ctx.now = next_deadlines.current_deadline;
}
grpc_exec_ctx_finish(&exec_ctx);
}
static void test_min_connect(void) {
grpc_backoff backoff;
const grpc_millis initial_backoff = 100;
const double multiplier = 1.0;
const double jitter = 0.0;
const grpc_millis min_connect_timeout = 200;
const grpc_millis max_backoff = 1000;
grpc_backoff_init(&backoff, initial_backoff, multiplier, jitter,
min_connect_timeout, max_backoff);
grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
grpc_backoff_result next = grpc_backoff_begin(&exec_ctx, &backoff);
// Because the min_connect_timeout > initial_backoff, current_deadline is used
// as the deadline for the current attempt.
GPR_ASSERT(next.current_deadline - grpc_exec_ctx_now(&exec_ctx) ==
min_connect_timeout);
// ... while, if the current attempt fails, the next one will happen after
// initial_backoff.
GPR_ASSERT(next.next_attempt_start_time - grpc_exec_ctx_now(&exec_ctx) ==
initial_backoff);
grpc_exec_ctx_finish(&exec_ctx);
}
static void test_no_jitter_backoff(void) {
grpc_backoff backoff;
const grpc_millis initial_backoff = 2;
const double multiplier = 2.0;
const double jitter = 0.0;
const grpc_millis min_connect_timeout = 1;
const grpc_millis max_backoff = 513;
grpc_backoff_init(&backoff, initial_backoff, multiplier, jitter,
min_connect_timeout, max_backoff);
// x_1 = 2
// x_n = 2**i + x_{i-1} ( = 2**(n+1) - 2 )
grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
exec_ctx.now = 0;
exec_ctx.now_is_valid = true;
grpc_backoff_result next_deadlines = grpc_backoff_begin(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline ==
next_deadlines.next_attempt_start_time);
GPR_ASSERT(next_deadlines.current_deadline == 2);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 6);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 14);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 30);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 62);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 126);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 254);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 510);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 1022);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
// Hit the maximum timeout. From this point onwards, retries will increase
// only by max timeout.
GPR_ASSERT(next_deadlines.current_deadline == 1535);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 2048);
exec_ctx.now = next_deadlines.current_deadline;
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline == 2561);
grpc_exec_ctx_finish(&exec_ctx);
}
static void test_jitter_backoff(void) {
const grpc_millis initial_backoff = 500;
grpc_millis current_backoff = initial_backoff;
const grpc_millis max_backoff = 1000;
const grpc_millis min_connect_timeout = 100;
const double multiplier = 1.0;
const double jitter = 0.1;
grpc_backoff backoff;
grpc_backoff_init(&backoff, initial_backoff, multiplier, jitter,
min_connect_timeout, max_backoff);
backoff.rng_state = 0; // force consistent PRNG
grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
grpc_backoff_result next_deadlines = grpc_backoff_begin(&exec_ctx, &backoff);
GPR_ASSERT(next_deadlines.current_deadline - grpc_exec_ctx_now(&exec_ctx) ==
initial_backoff);
GPR_ASSERT(next_deadlines.next_attempt_start_time -
grpc_exec_ctx_now(&exec_ctx) ==
initial_backoff);
grpc_millis expected_next_lower_bound =
(grpc_millis)((double)current_backoff * (1 - jitter));
grpc_millis expected_next_upper_bound =
(grpc_millis)((double)current_backoff * (1 + jitter));
for (int i = 0; i < 10000; i++) {
next_deadlines = grpc_backoff_step(&exec_ctx, &backoff);
// next-now must be within (jitter*100)% of the current backoff (which
// increases by * multiplier up to max_backoff).
const grpc_millis timeout_millis =
next_deadlines.current_deadline - grpc_exec_ctx_now(&exec_ctx);
GPR_ASSERT(timeout_millis >= expected_next_lower_bound);
GPR_ASSERT(timeout_millis <= expected_next_upper_bound);
current_backoff = GPR_MIN(
(grpc_millis)((double)current_backoff * multiplier), max_backoff);
expected_next_lower_bound =
(grpc_millis)((double)current_backoff * (1 - jitter));
expected_next_upper_bound =
(grpc_millis)((double)current_backoff * (1 + jitter));
exec_ctx.now = next_deadlines.current_deadline;
}
grpc_exec_ctx_finish(&exec_ctx);
}
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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