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nghttpx: Use gRPC's exponential backoff algorithm

This commit is contained in:
Tatsuhiro Tsujikawa 2016-04-05 22:31:27 +09:00
parent 46514074a4
commit ea5f424dec
1 changed files with 8 additions and 3 deletions
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11
src/shrpx_connect_blocker.cc
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@ -45,8 +45,12 @@ bool ConnectBlocker::blocked() const { return ev_is_active(&timer_); }
void ConnectBlocker::on_success() { fail_count_ = 0; } void ConnectBlocker::on_success() { fail_count_ = 0; }
// Use the similar backoff algorithm described in
// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md
namespace { namespace {
constexpr size_t MAX_BACKOFF_EXP = 10; constexpr size_t MAX_BACKOFF_EXP = 10;
constexpr auto MULTIPLIER = 1.6;
constexpr auto JITTER = 0.2;
} // namespace } // namespace
void ConnectBlocker::on_failure() { void ConnectBlocker::on_failure() {
@ -56,9 +60,10 @@ void ConnectBlocker::on_failure() {
++fail_count_; ++fail_count_;
auto max_backoff = (1 << std::min(MAX_BACKOFF_EXP, fail_count_)) - 1; auto base_backoff = pow(MULTIPLIER, std::min(MAX_BACKOFF_EXP, fail_count_));
auto dist = std::uniform_int_distribution<>(0, max_backoff); auto dist = std::uniform_real_distribution<>(-JITTER * base_backoff,
auto backoff = dist(gen_); JITTER * base_backoff);
auto backoff = base_backoff + dist(gen_);
LOG(WARN) << "Could not connect " << fail_count_ LOG(WARN) << "Could not connect " << fail_count_
<< " times in a row; sleep for " << backoff << " seconds"; << " times in a row; sleep for " << backoff << " seconds";