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-bit.lua | 91 ++++++++++++++++++--------
 1 file changed, 63 insertions(+), 28 deletions(-)

diff --git a/perf/LuaJIT-benches/mandelbrot-bit.lua b/perf/LuaJIT-benches/mandelbrot-bit.lua
index 91d96975..53c3ad4e 100644
--- a/perf/LuaJIT-benches/mandelbrot-bit.lua
+++ b/perf/LuaJIT-benches/mandelbrot-bit.lua
@@ -1,33 +1,68 @@
+-- The benchmark to check the performance of multiple inner loops
+-- with arithmetic operations. Bit variation. 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 bit = require("bit")
-local bor, band = bit.bor, bit.band
-local shl, shr, rol = bit.lshift, bit.rshift, bit.rol
-local write, char, unpack = io.write, string.char, unpack
-local N = tonumber(arg and arg[1]) or 100
-local M, buf = 2/N, {}
-write("P4\n", N, " ", N, "\n")
-for y=0,N-1 do
-  local Ci, b, p = y*M-1, -16777216, 0
-  local Ciq = Ci*Ci
-  for x=0,N-1,2 do
-    local Cr, Cr2 = x*M-1.5, (x+1)*M-1.5
-    local Zr, Zi, Zrq, Ziq = Cr, Ci, Cr*Cr, Ciq
-    local Zr2, Zi2, Zrq2, Ziq2 = Cr2, Ci, Cr2*Cr2, Ciq
-    b = rol(b, 2)
-    for i=1,49 do
-      Zi = Zr*Zi*2 + Ci; Zi2 = Zr2*Zi2*2 + Ci
-      Zr = Zrq-Ziq + Cr; Zr2 = Zrq2-Ziq2 + Cr2
-      Ziq = Zi*Zi; Ziq2 = Zi2*Zi2
-      Zrq = Zr*Zr; Zrq2 = Zr2*Zr2
-      if band(b, 2) ~= 0 and Zrq+Ziq > 4.0 then b = band(b, -3) end
-      if band(b, 1) ~= 0 and Zrq2+Ziq2 > 4.0 then b = band(b, -2) end
-      if band(b, 3) == 0 then 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 bor, band = bit.bor, bit.band
+  local shl, shr, rol = bit.lshift, bit.rshift, bit.rol
+  local write, char, unpack = io.write, string.char, unpack
+
+  local M, buf = 2 / N, {}
+  write("P4\n", N, " ", N, "\n")
+  for y = 0, N - 1 do
+    local Ci, b, p = y * M - 1, -16777216, 0
+    local Ciq = Ci * Ci
+    for x = 0, N - 1, 2 do
+      local Cr, Cr2 = x * M - 1.5, (x + 1) * M - 1.5
+      local Zr, Zi, Zrq, Ziq = Cr, Ci, Cr * Cr, Ciq
+      local Zr2, Zi2, Zrq2, Ziq2 = Cr2, Ci, Cr2 * Cr2, Ciq
+      b = rol(b, 2)
+      for i = 1, 49 do
+        Zi = Zr * Zi * 2 + Ci; Zi2 = Zr2 * Zi2 * 2 + Ci
+        Zr = Zrq - Ziq + Cr; Zr2 = Zrq2 - Ziq2 + Cr2
+        Ziq = Zi * Zi; Ziq2 = Zi2 * Zi2
+        Zrq = Zr * Zr; Zrq2 = Zr2 * Zr2
+        if band(b, 2) ~= 0 and Zrq + Ziq > 4.0 then b = band(b, -3) end
+        if band(b, 1) ~= 0 and Zrq2 + Ziq2 > 4.0 then b = band(b, -2) end
+        if band(b, 3) == 0 then break end
+      end
+      if b >= 0 then p = p + 1; buf[p] = b; b = -16777216; end
     end
-    if b >= 0 then p = p + 1; buf[p] = b; b = -16777216; end
-  end
-  if b ~= -16777216 then
-    if band(N, 1) ~= 0 then b = shr(b, 1) end
-    p = p + 1; buf[p] = shl(b, 8-band(N, 7))
+    if b ~= -16777216 then
+      if band(N, 1) ~= 0 then b = shr(b, 1) end
+      p = p + 1; buf[p] = shl(b, 8 - band(N, 7))
+    end
+    write(char(unpack(buf, 1, p)))
   end
-  write(char(unpack(buf, 1, p)))
 end
+
+local stdout = io.output()
+
+bench:add({
+  name = "mandelbrot_bit",
+  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()