New epoll event engine implemention that may be more effecient #295
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Signed-off-by: Coldwings <coldwings@me.com>
lihuiba
reviewed
Dec 10, 2023
| struct Poller { | ||
| int epfd = -1; | ||
| epoll_event events[16]; | ||
| int remains = 0; |
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put it right after epfd, to improve alignment.
| #define EPOLLRDHUP 0 | ||
| #endif | ||
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| class EventEngineEPollNG : public MasterEventEngine, |
io/epoll-ng.cpp
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| engine.collect(timeout); | ||
| engine.notify_all( | ||
| [&](epoll_data_t data) __INLINE__ { | ||
| if (data.fd == evfd) { |
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better to do it like this:
switch(data) {
case 0:
eventfd_read(evfd, &value);
break;
case 1:
rpoller.collect(0);
break;
case 2:
wpoller.collect(0);
break;
case 3:
epoller.collect(0);
break;
}so as to improve branch prediction
io/epoll-ng.cpp
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| return fired; | ||
| } | ||
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| void collect(uint64_t timeout) { |
io/epoll-ng.cpp
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| 0, [&](epoll_data_t data) __INLINE__ { *ptr++ = data.ptr; }, | ||
| [&]() | ||
| __INLINE__ { // make sure each fd receives all possible events | ||
| return (end - ptr) >= 3; |
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this seems not necessary any more?
io/epoll-ng.cpp
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| return ctl(fd, EPOLL_CTL_DEL, events, data); | ||
| } | ||
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| int wait(epoll_event* evs, size_t len, uint64_t timeout) { |
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wait() is only invoked by one-liner collect(). consider merging them.
Signed-off-by: Coldwings <coldwings@me.com>
lihuiba
reviewed
Dec 11, 2023
io/epoll-ng.cpp
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| Poller pl[4]; | ||
| Poller& engine = pl[(int)PULLERTYPE::ENGINE]; | ||
| Poller& rpoller = pl[(int)PULLERTYPE::READER]; |
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xpoller can be defined as macros instead. (x = r, w, e)
| return; | ||
| case (uint64_t)PULLERTYPE::EVENT: | ||
| eventfd_read(evfd, &value); | ||
| return; |
Signed-off-by: Coldwings <coldwings@me.com>
lihuiba
approved these changes
Dec 14, 2023
This pull request was closed.
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A new epoll event engine implementation (EPOLL_NG) which use epoll groups to manage read/write events.
This is much simpler and use no on-heap memory allocation, with better performance, as mentioned in #268
Edge-trigger related feature will be implemented in future.
New engine shows 3%~5% throughput/QPS improvement by
net-perftest.