GC pressure benchmark

callee.lua

local G = 0
function incG() G = G + 1 end

bench = {
  start = function()
    print(collectgarbage('count'))
    collectgarbage('collect')
    collectgarbage('stop')
    return collectgarbage('count')
  end,
  stop = function()
    local ret = collectgarbage('count')
    collectgarbage('restart')
    return ret
  end,
}

box.cfg({ listen = 9998, wal_mode = 'none' })
box.schema.user.grant('guest','execute','universe')

caller.lua

local nb = require('net.box')
local clock = require('clock')

local id, iterations = tonumber(arg[1]) or -1, tonumber(arg[2]) or 1e6

print(("===== %s: #%d ====="):format(_TARANTOOL, id))

local G = 0
function incG() G = G + 1 end

box.cfg({ listen = 9999, log = 'tarantool.log', wal_mode = 'none' })
box.schema.func.create('incG', { if_not_exists = true, language = 'LUA' })

collectgarbage('collect')
collectgarbage('stop')

local before = collectgarbage('count')
local start = clock.time64()

for _ = 1, iterations do box.func.incG:call() end

local stop = clock.time64()
local after = collectgarbage('count')

assert(G == iterations)

print(('call by ref GC: %f Kb'):format(after - before))
print(('call by ref time: %f sec'):format(tonumber(stop - start) / 1e9))

collectgarbage('restart')

local connection = nb.connect('localhost:9998')

local before = connection:call('bench.start')
local start = clock.time64()
for _ = 1, iterations do connection:call('incG') end
local stop = clock.time64()
local after = connection:call('bench.stop')

print(('call GC: %f Kb'):format(after - before))

local before = connection:call('bench.start')
local start = clock.time64()
for _ = 1, iterations do connection:eval('return incG()') end
local stop = clock.time64()
local after = connection:call('bench.stop')

print(('eval GC: %f Kb'):format(after - before))

os.exit(0)