[Tarantool-patches] [PATCH luajit 3/4] memprof: introduce the `--human-readable` option

[Maxim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

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
---
 .../gh-5994-memprof-human-readable.test.lua   | 72 +++++++++++++++++++
 tools/memprof.lua                             | 21 ++++--
 tools/memprof/humanize.lua                    | 46 +++++++++---
 3 files changed, 122 insertions(+), 17 deletions(-)
 create mode 100644 test/tarantool-tests/gh-5994-memprof-human-readable.test.lua

diff --git a/test/tarantool-tests/gh-5994-memprof-human-readable.test.lua b/test/tarantool-tests/gh-5994-memprof-human-readable.test.lua
new file mode 100644
index 00000000..0a579cec
--- /dev/null
+++ b/test/tarantool-tests/gh-5994-memprof-human-readable.test.lua
@@ -0,0 +1,72 @@
+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,
+})
+test:plan(5)
+
+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.
+}
+
+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)
diff --git a/tools/memprof.lua b/tools/memprof.lua
index e23bbf24..acadbc17 100644
--- a/tools/memprof.lua
+++ b/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
@@ -39,9 +45,12 @@ Supported options are:
   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 +110,11 @@ 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, symbols)
+  if not config.leak_only then
+    view.profile_info(events, config)
   end
-  local dheap = process.form_heap_delta(events, symbols)
-  view.leak_info(dheap)
+  local dheap = process.form_heap_delta(events)
+  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).
diff --git a/tools/memprof/humanize.lua b/tools/memprof/humanize.lua
index 5b289ce3..a5fdabf7 100644
--- a/tools/memprof/humanize.lua
+++ b/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 i = 1
+
+  while bytes >= 1024 and i < #units do
+    bytes = bytes / 1024
+    i = i + 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[i])
+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
-- 
2.43.0