memprof: introduce the --human-readable option

Prior to this patch, memprof could report only the raw
amount of bytes, which is hard to read. This patch adds the
`--human-readable` CLI option to the memprof parser, so the
memory is reported in KiB, MiB, or GiB, depending on what's
the biggest reasonable unit.

This patch also refactors the options mechanism for parser,
so all of the options are passed into parser's modules as a
single config table instead of being handled individually.

Part of tarantool/tarantool#5994

test/tarantool-tests/gh-5994-memprof-human-readable.test.lua

@@ -0,0 +1,73 @@
+local tap = require('tap')
+local test = tap.test('gh-5994-memprof-human-readable'):skipcond({
+  ['Profile tools are implemented for x86_64 only'] = jit.arch ~= 'x86' and
+                                                      jit.arch ~= 'x64',
+  ['Profile tools are implemented for Linux only'] = jit.os ~= 'Linux',
+  -- XXX: Tarantool integration is required to run this test properly.
+  -- luacheck: no global
+  ['No profile tools CLI option integration'] = _TARANTOOL,
+})
+
+local utils = require('utils')
+local TMP_BINFILE_MEMPROF = utils.tools.profilename('memprofdata.tmp.bin')
+local PARSE_CMD = utils.exec.luacmd(arg) .. ' -tm '
+
+local function generate_output(bytes)
+  local res, err = misc.memprof.start(TMP_BINFILE_MEMPROF)
+  -- Should start successfully.
+  assert(res, err)
+
+  -- luacheck: no unused
+  local _ = string.rep('_', bytes)
+
+  res, err = misc.memprof.stop()
+  -- Should stop successfully.
+  assert(res, err)
+end
+
+local TEST_SET = {
+  {
+    bytes = 2049,
+    match = '%dB',
+    hr = false,
+    name = 'non-human-readable mode is correct'
+  },
+  {
+    bytes = 100,
+    match = '%dB',
+    hr = true,
+    name = 'human-readable mode: bytes'
+  },
+  {
+    bytes = 2560,
+    match = '%d+%.%d%dKiB',
+    hr = true,
+    name = 'human-readable mode: float'
+  },
+  {
+    bytes = 2048,
+    match = '%dKiB',
+    hr = true,
+    name = 'human-readable mode: KiB'
+  },
+  {
+    bytes = 1024 * 1024,
+    match = '%dMiB',
+    hr = true,
+    name = 'human-readable mode: MiB'
+  },
+  -- XXX: The test case for GiB is not implemented because it is
+  -- OOM-prone for non-GC64 builds.
+}
+
+test:plan(#TEST_SET)
+
+for _, params in ipairs(TEST_SET) do
+  generate_output(params.bytes)
+  local cmd = PARSE_CMD .. (params.hr and ' --human-readable ' or '')
+  local output = io.popen(cmd .. TMP_BINFILE_MEMPROF):read('*all')
+  test:like(output, params.match, params.name)
+end
+
+os.remove(TMP_BINFILE_MEMPROF)
+test:done(true)

tools/memprof.lua

@@ -22,6 +22,12 @@ local match, gmatch = string.match, string.gmatch
 -- Program options.
 local opt_map = {}
 
+-- Default config for the memprof parser.
+local config = {
+  leak_only = false,
+  human_readable = false,
+}
+
 function opt_map.help()
   stdout:write [[
 luajit-parse-memprof - parser of the memory usage profile collected
@@ -34,14 +40,18 @@ luajit-parse-memprof [options] memprof.bin
 Supported options are:
 
   --help                            Show this help and exit
+  --human-readable                  Use KiB/MiB/GiB notation instead of bytes
   --leak-only                       Report only leaks information
 ]]
   os.exit(0)
 end
 
-local leak_only = false
 opt_map["leak-only"] = function()
-  leak_only = true
+  config.leak_only = true
+end
+
+opt_map["human-readable"] = function()
+  config.human_readable = true
 end
 
 -- Print error and exit with error status.
@@ -101,11 +111,11 @@ local function dump(inputfile)
   local reader = bufread.new(inputfile)
   local symbols = symtab.parse(reader)
   local events = memprof.parse(reader, symbols)
-  if not leak_only then
-    view.profile_info(events)
+  if not config.leak_only then
+    view.profile_info(events, config)
   end
   local dheap = process.form_heap_delta(events)
-  view.leak_info(dheap)
+  view.leak_info(dheap, config)
   view.aliases(symbols)
   -- XXX: The second argument is required to properly close Lua
   -- universe (i.e. invoke <lua_close> before exiting).

tools/memprof/humanize.lua

@@ -5,7 +5,29 @@
 
 local M = {}
 
-function M.render(events)
+local function human_readable_bytes(bytes)
+  local units = {"B", "KiB", "MiB", "GiB"}
+  local magnitude = 1
+
+  while bytes >= 1024 and magnitude < #units do
+    bytes = bytes / 1024
+    magnitude = magnitude + 1
+  end
+  local is_int = math.floor(bytes) == bytes
+  local fmt = is_int and "%d%s" or "%.2f%s"
+
+  return string.format(fmt, bytes, units[magnitude])
+end
+
+local function format_bytes(bytes, config)
+  if config.human_readable then
+    return human_readable_bytes(bytes)
+  else
+    return string.format('%dB', bytes)
+  end
+end
+
+function M.render(events, config)
   local ids = {}
 
   for id, _ in pairs(events) do
@@ -18,11 +40,11 @@ function M.render(events)
 
   for i = 1, #ids do
     local event = events[ids[i]]
-    print(string.format("%s: %d events\t+%d bytes\t-%d bytes",
+    print(string.format("%s: %d events\t+%s\t-%s",
       event.loc,
       event.num,
-      event.alloc,
-      event.free
+      format_bytes(event.alloc, config),
+      format_bytes(event.free, config)
     ))
 
     local prim_loc = {}
@@ -40,21 +62,21 @@ function M.render(events)
   end
 end
 
-function M.profile_info(events)
+function M.profile_info(events, config)
   print("ALLOCATIONS")
-  M.render(events.alloc)
+  M.render(events.alloc, config)
   print("")
 
   print("REALLOCATIONS")
-  M.render(events.realloc)
+  M.render(events.realloc, config)
   print("")
 
   print("DEALLOCATIONS")
-  M.render(events.free)
+  M.render(events.free, config)
   print("")
 end
 
-function M.leak_info(dheap)
+function M.leak_info(dheap, config)
   local leaks = {}
   for line, info in pairs(dheap) do
     -- Report "INTERNAL" events inconsistencies for profiling
@@ -71,8 +93,10 @@ function M.leak_info(dheap)
   print("HEAP SUMMARY:")
   for _, l in pairs(leaks) do
     print(string.format(
-      "%s holds %d bytes: %d allocs, %d frees",
-      l.line, l.dbytes, dheap[l.line].nalloc,
+      "%s holds %s: %d allocs, %d frees",
+      l.line,
+      format_bytes(l.dbytes, config),
+      dheap[l.line].nalloc,
       dheap[l.line].nfree
     ))
   end