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util/statistics.lua @ 7543:23a8a26e8912
net.server: Fix whitespace
author | Kim Alvefur <zash@zash.se> |
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date | Wed, 10 Aug 2016 16:44:59 +0200 |
parent | 6649:99fa40d498cc |
child | 7988:dc758422d896 |
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local t_sort = table.sort local m_floor = math.floor; local time = require "socket".gettime; local function nop_function() end local function percentile(arr, length, pc) local n = pc/100 * (length + 1); local k, d = m_floor(n), n%1; if k == 0 then return arr[1] or 0; elseif k >= length then return arr[length]; end return arr[k] + d*(arr[k+1] - arr[k]); end local function new_registry(config) config = config or {}; local duration_sample_interval = config.duration_sample_interval or 5; local duration_max_samples = config.duration_max_stored_samples or 5000; local function get_distribution_stats(events, n_actual_events, since, new_time, units) local n_stored_events = #events; t_sort(events); local sum = 0; for i = 1, n_stored_events do sum = sum + events[i]; end return { samples = events; sample_count = n_stored_events; count = n_actual_events, rate = n_actual_events/(new_time-since); average = n_stored_events > 0 and sum/n_stored_events or 0, min = events[1] or 0, max = events[n_stored_events] or 0, units = units, }; end local registry = {}; local methods; methods = { amount = function (name, initial) local v = initial or 0; registry[name..":amount"] = function () return "amount", v; end return function (new_v) v = new_v; end end; counter = function (name, initial) local v = initial or 0; registry[name..":amount"] = function () return "amount", v; end return function (delta) v = v + delta; end; end; rate = function (name) local since, n = time(), 0; registry[name..":rate"] = function () local t = time(); local stats = { rate = n/(t-since); count = n; }; since, n = t, 0; return "rate", stats.rate, stats; end; return function () n = n + 1; end; end; distribution = function (name, unit, type) type = type or "distribution"; local events, last_event = {}, 0; local n_actual_events = 0; local since = time(); registry[name..":"..type] = function () local new_time = time(); local stats = get_distribution_stats(events, n_actual_events, since, new_time, unit); events, last_event = {}, 0; n_actual_events = 0; since = new_time; return type, stats.average, stats; end; return function (value) n_actual_events = n_actual_events + 1; if n_actual_events%duration_sample_interval == 1 then last_event = (last_event%duration_max_samples) + 1; events[last_event] = value; end end; end; sizes = function (name) return methods.distribution(name, "bytes", "size"); end; times = function (name) local events, last_event = {}, 0; local n_actual_events = 0; local since = time(); registry[name..":duration"] = function () local new_time = time(); local stats = get_distribution_stats(events, n_actual_events, since, new_time, "seconds"); events, last_event = {}, 0; n_actual_events = 0; since = new_time; return "duration", stats.average, stats; end; return function () n_actual_events = n_actual_events + 1; if n_actual_events%duration_sample_interval ~= 1 then return nop_function; end local start_time = time(); return function () local end_time = time(); local duration = end_time - start_time; last_event = (last_event%duration_max_samples) + 1; events[last_event] = duration; end end; end; get_stats = function () return registry; end; }; return methods; end return { new = new_registry; get_histogram = function (duration, n_buckets) n_buckets = n_buckets or 100; local events, n_events = duration.samples, duration.sample_count; if not (events and n_events) then return nil, "not a valid distribution stat"; end local histogram = {}; for i = 1, 100, 100/n_buckets do histogram[i] = percentile(events, n_events, i); end return histogram; end; get_percentile = function (duration, pc) local events, n_events = duration.samples, duration.sample_count; if not (events and n_events) then return nil, "not a valid distribution stat"; end return percentile(events, n_events, pc); end; }