line width benchmarks

benchmark.lua

local function old(msg)
  return math.max(math.max(unpack(vim.tbl_map(function(line)
    return vim.fn.strchars(line)
  end, msg))))
end

local max = math.max
local strwidth = vim.api.nvim_strwidth or vim.fn.strchars

local function new(msg)
  local width = 0

  if msg then
    for i = 1, #msg do
      width = max(width, strwidth(msg[i]))
    end
  end

  return width
end

-- https://github.com/flrgh/lua-utils/blob/main/lib/flrgh/bench.lua
local bench = require "flrgh.bench"

local saved = _G.print
local fh = assert(io.open("data.txt", "w"))
_G.print = function(s)
  if s then fh:write(s) end
  fh:write("\n")
end

for _, num_lines in ipairs({ 10, 100, 1000 }) do
  for _, max_width in ipairs({ 10, 100, 1000 }) do
    local lines = require("table.new")(num_lines, 0)
    for i = 1, num_lines do
      lines[i] = string.rep("x", math.random(1, max_width))
    end

    -- ensure at least one line is of max width
    lines[math.random(1, num_lines)] = string.rep("x", max_width)

    bench.many(
      {
        count = 1000,
        title = ("lines: %s, max width: %s"):format(num_lines, max_width),
        warmup = true,
      },
      {
        {
          name = "old",
          func = old,
        },
        {
          name = "new",
          func = new,
        },
      },
      lines
    )
  end
end

fh:close()
_G.print = saved

data.txt

+--------------------------------------------+
| lines: 10, max width: 10 (1000 iterations) |
+--------------------------------------------+
| func                 | total(ms) | avg(us) |
+--------------------------------------------+
| old                  | 7.542     | 7.542   |
| new                  | 0.592     | 0.592   |
+--------------------------------------------+

+---------------------------------------------+
| lines: 10, max width: 100 (1000 iterations) |
+---------------------------------------------+
| func                  | total(ms) | avg(us) |
+---------------------------------------------+
| old                   | 5.297     | 5.297   |
| new                   | 1.567     | 1.567   |
+---------------------------------------------+

+----------------------------------------------+
| lines: 10, max width: 1000 (1000 iterations) |
+----------------------------------------------+
| func                   | total(ms) | avg(us) |
+----------------------------------------------+
| old                    | 25.95     | 25.95   |
| new                    | 10.174    | 10.174  |
+----------------------------------------------+

+---------------------------------------------+
| lines: 100, max width: 10 (1000 iterations) |
+---------------------------------------------+
| func                  | total(ms) | avg(us) |
+---------------------------------------------+
| old                   | 24.393    | 24.393  |
| new                   | 6.366     | 6.366   |
+---------------------------------------------+

+----------------------------------------------+
| lines: 100, max width: 100 (1000 iterations) |
+----------------------------------------------+
| func                   | total(ms) | avg(us) |
+----------------------------------------------+
| old                    | 42.714    | 42.714  |
| new                    | 14.168    | 14.168  |
+----------------------------------------------+

+-----------------------------------------------+
| lines: 100, max width: 1000 (1000 iterations) |
+-----------------------------------------------+
| func                    | total(ms) | avg(us) |
+-----------------------------------------------+
| old                     | 224.771   | 224.771 |
| new                     | 90.084    | 90.084  |
+-----------------------------------------------+

+----------------------------------------------+
| lines: 1000, max width: 10 (1000 iterations) |
+----------------------------------------------+
| func                   | total(ms) | avg(us) |
+----------------------------------------------+
| old                    | 239.586   | 239.586 |
| new                    | 64.684    | 64.684  |
+----------------------------------------------+

+-----------------------------------------------+
| lines: 1000, max width: 100 (1000 iterations) |
+-----------------------------------------------+
| func                    | total(ms) | avg(us) |
+-----------------------------------------------+
| old                     | 422.562   | 422.562 |
| new                     | 144.566   | 144.566 |
+-----------------------------------------------+

+------------------------------------------------+
| lines: 1000, max width: 1000 (1000 iterations) |
+------------------------------------------------+
| func                    | total(ms) | avg(us)  |
+------------------------------------------------+
| old                     | 2290.113  | 2290.113 |
| new                     | 926.801   | 926.801  |
+------------------------------------------------+