1dff107de1
Motivation: The Epoll transport checks to see if there are any scheduled tasks before entering epoll_wait, and resets the timerfd just before. This causes an extra syscall to timerfd_settime before doing any actual work. When scheduled tasks aren't added frequently, or tasks are added with later deadlines, this is unnecessary. Modification: Check the *deadline* of the peeked task in EpollEventLoop, rather than the *delay*. If it hasn't changed since last time, don't re-arm the timer Result: About 2us faster on gRPC RTT 50pct latency benchmarks. Before (2 runs for 5 minutes, 1 minute of warmup): ``` 50.0%ile Latency (in nanos): 64267 90.0%ile Latency (in nanos): 72851 95.0%ile Latency (in nanos): 78903 99.0%ile Latency (in nanos): 92327 99.9%ile Latency (in nanos): 119691 100.0%ile Latency (in nanos): 13347327 QPS: 14933 50.0%ile Latency (in nanos): 63907 90.0%ile Latency (in nanos): 73055 95.0%ile Latency (in nanos): 79443 99.0%ile Latency (in nanos): 93739 99.9%ile Latency (in nanos): 123583 100.0%ile Latency (in nanos): 14028287 QPS: 14936 ``` After: ``` 50.0%ile Latency (in nanos): 62123 90.0%ile Latency (in nanos): 70795 95.0%ile Latency (in nanos): 76895 99.0%ile Latency (in nanos): 90887 99.9%ile Latency (in nanos): 117819 100.0%ile Latency (in nanos): 14126591 QPS: 15387 50.0%ile Latency (in nanos): 61021 90.0%ile Latency (in nanos): 70311 95.0%ile Latency (in nanos): 76687 99.0%ile Latency (in nanos): 90887 99.9%ile Latency (in nanos): 119527 100.0%ile Latency (in nanos): 6351615 QPS: 15571 ``` |
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| pom.xml | ||