hnlq715 commented on a change in pull request #3300: URL: https://github.com/apache/apisix/pull/3300#discussion_r559277437
########## File path: apisix/balancer/ewma.lua ########## @@ -3,105 +3,125 @@ -- Inspiration drawn from: -- https://github.com/twitter/finagle/blob/1bc837c4feafc0096e43c0e98516a8e1c50c4421 -- /finagle-core/src/main/scala/com/twitter/finagle/loadbalancer/PeakEwma.scala - local core = require("apisix.core") +local nkeys = require("core.table.nkeys") +local resty_lock = require("resty.lock") + local ngx = ngx local ngx_shared = ngx.shared local ngx_now = ngx.now local math = math local pairs = pairs local next = next +local error = error -local _M = {} local DECAY_TIME = 10 -- this value is in seconds +local LOCK_KEY = ":ewma_key" local shm_ewma = ngx_shared.balancer_ewma -local shm_last_touched_at= ngx_shared.balancer_ewma_last_touched_at +local shm_last_touched_at = ngx_shared.balancer_ewma_last_touched_at + +local lrucache_addr = core.lrucache.new({ttl = 300, count = 1024}) +local lrucache_trans_format = core.lrucache.new({ttl = 300, count = 256}) + +local ewma_lock, ewma_lock_err = resty_lock:new("balancer_ewma_locks", + {timeout = 0, exptime = 0.1}) + +local _M = {name = "ewma"} + +local function lock(upstream) + local _, err = ewma_lock:lock(upstream .. LOCK_KEY) + if err then + if err ~= "timeout" then + core.log.error("EWMA Balancer failed to lock: ", err) + end + end + + return err +end -local lrucache_addr = core.lrucache.new({ - ttl = 300, count = 1024 -}) -local lrucache_trans_format = core.lrucache.new({ - ttl = 300, count = 256 -}) +local function unlock() + local ok, err = ewma_lock:unlock() + if not ok then + core.log.error("EWMA Balancer failed to unlock: ", err) + end + return err +end local function decay_ewma(ewma, last_touched_at, rtt, now) local td = now - last_touched_at - td = math.max(td, 0) + td = (td > 0) and td or 0 local weight = math.exp(-td / DECAY_TIME) ewma = ewma * weight + rtt * (1.0 - weight) return ewma end - local function store_stats(upstream, ewma, now) local success, err, forcible = shm_last_touched_at:set(upstream, now) if not success then - core.log.error("balancer_ewma_last_touched_at:set failed ", err) + core.log.warn("shm_last_touched_at:set failed: ", err) Review comment: This error often came out when the dict is full, but everything goes fine because we can evict the old items in the dict. Refer to ingress-nginx, so maybe warn is a proper level? :-) https://github.com/kubernetes/ingress-nginx/blob/master/rootfs/etc/nginx/lua/balancer/ewma.lua#L68 ########## File path: apisix/balancer/ewma.lua ########## @@ -3,105 +3,125 @@ -- Inspiration drawn from: -- https://github.com/twitter/finagle/blob/1bc837c4feafc0096e43c0e98516a8e1c50c4421 -- /finagle-core/src/main/scala/com/twitter/finagle/loadbalancer/PeakEwma.scala - local core = require("apisix.core") +local nkeys = require("core.table.nkeys") +local resty_lock = require("resty.lock") + local ngx = ngx local ngx_shared = ngx.shared local ngx_now = ngx.now local math = math local pairs = pairs local next = next +local error = error -local _M = {} local DECAY_TIME = 10 -- this value is in seconds +local LOCK_KEY = ":ewma_key" local shm_ewma = ngx_shared.balancer_ewma -local shm_last_touched_at= ngx_shared.balancer_ewma_last_touched_at +local shm_last_touched_at = ngx_shared.balancer_ewma_last_touched_at + +local lrucache_addr = core.lrucache.new({ttl = 300, count = 1024}) +local lrucache_trans_format = core.lrucache.new({ttl = 300, count = 256}) + +local ewma_lock, ewma_lock_err = resty_lock:new("balancer_ewma_locks", + {timeout = 0, exptime = 0.1}) + +local _M = {name = "ewma"} + +local function lock(upstream) + local _, err = ewma_lock:lock(upstream .. LOCK_KEY) + if err then + if err ~= "timeout" then + core.log.error("EWMA Balancer failed to lock: ", err) + end + end + + return err +end -local lrucache_addr = core.lrucache.new({ - ttl = 300, count = 1024 -}) -local lrucache_trans_format = core.lrucache.new({ - ttl = 300, count = 256 -}) +local function unlock() + local ok, err = ewma_lock:unlock() + if not ok then + core.log.error("EWMA Balancer failed to unlock: ", err) + end + return err +end local function decay_ewma(ewma, last_touched_at, rtt, now) local td = now - last_touched_at - td = math.max(td, 0) + td = (td > 0) and td or 0 local weight = math.exp(-td / DECAY_TIME) ewma = ewma * weight + rtt * (1.0 - weight) return ewma end - local function store_stats(upstream, ewma, now) local success, err, forcible = shm_last_touched_at:set(upstream, now) if not success then - core.log.error("balancer_ewma_last_touched_at:set failed ", err) + core.log.warn("shm_last_touched_at:set failed: ", err) end if forcible then - core.log.warn("balancer_ewma_last_touched_at:set valid items forcibly overwritten") + core.log Review comment: Because the max column number is set to `80` so this line break into two lines by format tool, I fixed it by setting it to `82`. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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