[Tarantool-patches] [PATCH] serializer: serialize recursive structures

[Sergey Bronnikov]

On 21.04.2021 12:27, Sergey Kaplun via Tarantool-patches wrote:
> Hi!
>
> Thanks for the fixes and the benchmarks!

I propose an updated version of script and propose to add benchmark as a 
part of patch series.

--[[
-- measure serialization time
-- run: taskset -c 1 tarantool perf.lua
]]

local clock = require('clock')

local function elapsed(f, n)
     local t0 = clock.monotonic()
     for i = 1, n do
         f()
     end
     local t1 = clock.monotonic()
     return t1 - t0
end

-- Get the mean of a table
function calculate_mean(t)
   local sum = 0
   local count= 0
   for k, v in pairs(t) do
     if type(v) == 'number' then
       sum = sum + v
     end
   end

   return (sum/#t)
end

-- Get the median of a table.
function calculate_median(t)
   local temp = {}
   -- deep copy table so that when we sort it, the original is unchanged
   -- also weed out any non numbers
   for k, v in pairs(t) do
     if type(v) == 'number' then
       table.insert(temp, v)
     end
   end
   table.sort(temp)
   -- If we have an even number of table elements or odd.
   if math.fmod(#temp,2) == 0 then
     -- return mean value of middle two elements
     return (temp[#temp/2] + temp[(#temp/2)+1]) / 2
   else
     -- return middle element
     return temp[math.ceil(#temp/2)]
   end
end

-- Get the standard deviation of a table
function calculate_stddev(t)
   local vm
   local sum = 0
   local mean = calculate_mean(t)
   for k, v in pairs(t) do
     if type(v) == 'number' then
       vm = v - mean
       sum = sum + (vm * vm)
     end
   end

   return math.sqrt(sum/(#t - 1))
end

local function timeit(f, name)
     print('======================================')
     print(name)
     print('======================================')
     local res = {}
     local iterations = 10
     local elapsed_time = 0
     local repetitions = 150000
     for j = 1, iterations do
         -- warming
         for i = 1, 100 do f() end
         -- measurement
         elapsed_time = elapsed(f, repetitions)
         table.insert(res, elapsed_time)
         print(string.format("%-2d - %f sec / %d repetitions", j, 
elapsed_time, repetitions))
     end
     print(string.format("time mean   %f", calculate_mean(res)))
     print(string.format("time median %f", calculate_median(res)))
     print(string.format("time stddev %f", calculate_stddev(res)))
end

local t = {{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}
timeit(function()
            local console = require('console')
            console.set_default_output('yaml')
            return console.eval(tostring(t))
        end, 'serializer console yaml')
timeit(function()
            local console = require('console')
            console.set_default_output('lua')
            return console.eval(tostring(t))
        end, 'serializer console lua')
timeit(function()
            local serializer = require('json')
            serializer.cfg({encode_max_depth = 64})
            return serializer.encode(t)
        end, 'serializer json')
timeit(function()
            local serializer = require('yaml')
            serializer.cfg({encode_max_depth = 64})
            return serializer.encode(t)
        end, 'serializer yaml')
timeit(function()
            local serializer = require('msgpack')
            serializer.cfg({encode_max_depth = 64})
            return serializer.encode(t)
        end, 'serializer msgpack')
timeit(function()
            local serializer = require('msgpackffi')
            return serializer.encode(t)
        end, 'serializer msgpackffi')