Hi, Sergey!

thanks for the patch! LGTM

Sergey

This patch adjusts the aforementioned test to use the benchmark
framework introduced before. The default arguments are adjusted
according to the <PARAM_x86.txt> file. The arguments to the script still
can be provided in the command line run.

The output is redirected to /dev/null. The check is skipped since it is
very inconvenient to check the binary output, especially since it may be
configured by the parameter.
---
 perf/LuaJIT-benches/mandelbrot.lua | 70 ++++++++++++++++++++++--------
 1 file changed, 51 insertions(+), 19 deletions(-)

diff --git a/perf/LuaJIT-benches/mandelbrot.lua b/perf/LuaJIT-benches/mandelbrot.lua
index 0ef595a2..999ff200 100644
--- a/perf/LuaJIT-benches/mandelbrot.lua
+++ b/perf/LuaJIT-benches/mandelbrot.lua
@@ -1,23 +1,55 @@
+-- The benchmark to check the performance of multiple inner loops
+-- with arithmetic operations. Calculates the Mandelbrot Set on a
+-- bitmap and dumps output in the portable bitmap format.
+-- For the details see:
+-- https://benchmarksgame-team.pages.debian.net/benchmarksgame/description/mandelbrot.html
 
-local write, char, unpack = io.write, string.char, unpack
-local N = tonumber(arg and arg[1]) or 100
-local M, ba, bb, buf = 2/N, 2^(N%8+1)-1, 2^(8-N%8), {}
-write("P4\n", N, " ", N, "\n")
-for y=0,N-1 do
-  local Ci, b, p = y*M-1, 1, 0
-  for x=0,N-1 do
-    local Cr = x*M-1.5
-    local Zr, Zi, Zrq, Ziq = Cr, Ci, Cr*Cr, Ci*Ci
-    b = b + b
-    for i=1,49 do
-      Zi = Zr*Zi*2 + Ci
-      Zr = Zrq-Ziq + Cr
-      Ziq = Zi*Zi
-      Zrq = Zr*Zr
-      if Zrq+Ziq > 4.0 then b = b + 1; break; end
+local bench = require("bench").new(arg)
+
+local N = tonumber(arg and arg[1]) or 5000
+
+local function payload()
+  -- These functions must not be an upvalue but the stack slot.
+  local N = N
+  local write, char, unpack = io.write, string.char, unpack
+  local M, ba, bb, buf = 2 / N, 2 ^ (N % 8 + 1) - 1, 2 ^ (8 - N % 8), {}
+  write("P4\n", N, " ", N, "\n")
+  for y = 0, N - 1 do
+    local Ci, b, p = y * M - 1, 1, 0
+    for x = 0, N - 1 do
+      local Cr = x * M - 1.5
+      local Zr, Zi, Zrq, Ziq = Cr, Ci, Cr * Cr, Ci * Ci
+      b = b + b
+      for i = 1, 49 do
+        Zi = Zr * Zi * 2 + Ci
+        Zr = Zrq - Ziq + Cr
+        Ziq = Zi * Zi
+        Zrq = Zr * Zr
+        if Zrq + Ziq > 4.0 then b = b + 1; break; end
+      end
+      if b >= 256 then p = p + 1; buf[p] = 511 - b; b = 1; end
     end
-    if b >= 256 then p = p + 1; buf[p] = 511 - b; b = 1; end
+    if b ~= 1 then p = p + 1; buf[p] = (ba - b) * bb; end
+    write(char(unpack(buf, 1, p)))
   end
-  if b ~= 1 then p = p + 1; buf[p] = (ba-b)*bb; end
-  write(char(unpack(buf, 1, p)))
 end
+
+local stdout = io.output()
+
+bench:add({
+  name = "mandelbrot",
+  items = N,
+  -- XXX: This is inconvenient to have the binary file in the
+  -- repository for the comparison. If the check is needed run,
+  -- the payload manually.
+  skip_check = true,
+  setup = function()
+    io.output("/dev/null")
+  end,
+  teardown = function()
+    io.output(stdout)
+  end,
+  payload = payload,
+})
+
+bench:run_and_report()