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net/server_epoll.lua @ 10059:c8c3f2eba898 0.11
net.server_epoll: Backport timer optimization 6c2370f17027 from trunk (see #1388)
The previous timer handling did not scale well and led to high CPU usage
with many connections (each with at least an read timeout).
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Mon, 08 Jul 2019 01:17:34 +0200 |
parent | 9994:524b8cd76780 |
child | 10061:5c71693c8345 |
child | 10681:e531273341d3 |
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--- a/net/server_epoll.lua Thu Jun 20 22:25:46 2019 +0200 +++ b/net/server_epoll.lua Mon Jul 08 01:17:34 2019 +0200 @@ -6,9 +6,7 @@ -- -local t_sort = table.sort; local t_insert = table.insert; -local t_remove = table.remove; local t_concat = table.concat; local setmetatable = setmetatable; local tostring = tostring; @@ -20,6 +18,7 @@ local socket = require "socket"; local luasec = require "ssl"; local gettime = require "util.time".now; +local indexedbheap = require "util.indexedbheap"; local createtable = require "util.table".create; local inet = require "util.net"; local inet_pton = inet.pton; @@ -66,22 +65,24 @@ -- Timer and scheduling -- -local timers = {}; +local timers = indexedbheap.create(); local function noop() end local function closetimer(t) t[1] = 0; t[2] = noop; + timers:remove(t.id); end --- Set to true when timers have changed -local resort_timers = false; +local function reschedule(t, time) + t[1] = time; + timers:reprioritize(t.id, time); +end -- Add absolute timer local function at(time, f) - local timer = { time, f, close = closetimer }; - t_insert(timers, timer); - resort_timers = true; + local timer = { time, f, close = closetimer, reschedule = reschedule, id = nil }; + timer.id = timers:insert(timer, time); return timer; end @@ -94,50 +95,32 @@ -- Return time until next timeout local function runtimers(next_delay, min_wait) -- Any timers at all? - if not timers[1] then + local now = gettime(); + local peek = timers:peek(); + while peek do + + if peek > now then + next_delay = peek - now; + break; + end + + local _, timer, id = timers:pop(); + local ok, ret = pcall(timer[2], now); + if ok and type(ret) == "number" then + local next_time = now+ret; + timer[1] = next_time; + timers:insert(timer, next_time); + end + + peek = timers:peek(); + end + if peek == nil then return next_delay; end - if resort_timers then - -- Sort earliest timers to the end - t_sort(timers, function (a, b) return a[1] > b[1]; end); - resort_timers = false; + if next_delay < min_wait then + return min_wait; end - - -- Iterate from the end and remove completed timers - for i = #timers, 1, -1 do - local timer = timers[i]; - local t, f = timer[1], timer[2]; - -- Get time for every iteration to increase accuracy - local now = gettime(); - if t > now then - -- This timer should not fire yet - local diff = t - now; - if diff < next_delay then - next_delay = diff; - end - break; - end - local new_timeout = f(now); - if new_timeout then - -- Schedule for 'delay' from the time actually scheduled, - -- not from now, in order to prevent timer drift. - timer[1] = t + new_timeout; - resort_timers = true; - else - t_remove(timers, i); - end - end - - if resort_timers or next_delay < min_wait then - -- Timers may be added from within a timer callback. - -- Those would not be considered for next_delay, - -- and we might sleep for too long, so instead - -- we return a shorter timeout so we can - -- properly sort all new timers. - next_delay = min_wait; - end - return next_delay; end @@ -243,8 +226,7 @@ end t = t or cfg.read_timeout; if self._readtimeout then - self._readtimeout[1] = gettime() + t; - resort_timers = true; + self._readtimeout:reschedule(gettime() + t); else self._readtimeout = addtimer(t, function () if self:on("readtimeout") then @@ -268,8 +250,7 @@ end t = t or cfg.send_timeout; if self._writetimeout then - self._writetimeout[1] = gettime() + t; - resort_timers = true; + self._writetimeout:reschedule(gettime() + t); else self._writetimeout = addtimer(t, function () self:on("disconnect", "write timeout");