add luajit platform metrics

After tarantool/tarantool#5187 tarantool
could report luajit platform metrics.

This patch exports them as default metrics.
For detailed description of each metric see
tarantool/doc#1597.

Closes #127

Author: olegrok

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Luajit platform metrics
 
 ## [0.5.0] - 2020-09-18
 ### Added

metrics-scm-1.rockspec

@@ -38,6 +38,7 @@ build = {
         ['metrics.default_metrics.tarantool']            = 'metrics/default_metrics/tarantool/init.lua',
         ['metrics.default_metrics.tarantool.fibers']     = 'metrics/default_metrics/tarantool/fibers.lua',
         ['metrics.default_metrics.tarantool.info']       = 'metrics/default_metrics/tarantool/info.lua',
+        ['metrics.default_metrics.tarantool.luajit']     = 'metrics/default_metrics/tarantool/luajit.lua',
         ['metrics.default_metrics.tarantool.memory']     = 'metrics/default_metrics/tarantool/memory.lua',
         ['metrics.default_metrics.tarantool.network']    = 'metrics/default_metrics/tarantool/network.lua',
         ['metrics.default_metrics.tarantool.operations'] = 'metrics/default_metrics/tarantool/operations.lua',

metrics/default_metrics/tarantool/init.lua

@@ -11,6 +11,7 @@ local default_metrics = {
     require('metrics.default_metrics.tarantool.memory'),
     require('metrics.default_metrics.tarantool.spaces'),
     require('metrics.default_metrics.tarantool.fibers'),
+    require('metrics.default_metrics.tarantool.luajit'),
 }
 
 local function enable()

metrics/default_metrics/tarantool/luajit.lua

@@ -0,0 +1,72 @@
+local metrics = require('metrics')
+
+local has_mics_module, misc = pcall(require, 'misc')
+
+local gauges_storage = {}
+
+local LJ_PREFIX = 'lj_'
+
+local function prefix_name(name)
+    return LJ_PREFIX .. name
+end
+
+local function set_gauge(name, description, value, labels)
+    if (gauges_storage[name] == nil) then
+        gauges_storage[name] = metrics.gauge(prefix_name(name), description)
+    end
+
+    gauges_storage[name]:set(value, labels or {})
+end
+
+local function update_lj_metrics()
+    -- Details: https://github.com/tarantool/doc/issues/1597
+    local lj_metrics = misc.getmetrics()
+    set_gauge('gc_freed', 'Total amount of freed memory',
+        lj_metrics.gc_freed)
+    set_gauge('strhash_hit', 'Number of strings being interned',
+        lj_metrics.strhash_hit)
+    set_gauge('gc_steps_atomic', 'Count of incremental GC steps (atomic state)',
+        lj_metrics.gc_steps_atomic)
+    set_gauge('strhash_miss', 'Total number of strings allocations during the platform lifetime',
+        lj_metrics.strhash_miss)
+    set_gauge('gc_steps_sweepstring', 'Count of incremental GC steps (sweepstring state)',
+        lj_metrics.gc_steps_sweepstring)
+    set_gauge('gc_strnum', 'Amount of allocated string objects',
+        lj_metrics.gc_strnum)
+    set_gauge('gc_tabnum', 'Amount of allocated table objects',
+        lj_metrics.gc_tabnum)
+    set_gauge('gc_cdatanum', 'Amount of allocated cdata objects',
+        lj_metrics.gc_cdatanum)
+    set_gauge('jit_snap_restore', 'Overall number of snap restores',
+        lj_metrics.jit_snap_restore)
+    set_gauge('gc_total', 'Memory currently allocated',
+        lj_metrics.gc_total)
+    set_gauge('gc_udatanum', 'Amount of allocated udata objects',
+        lj_metrics.gc_udatanum)
+    set_gauge('gc_steps_finalize', 'Count of incremental GC steps (finalize state)',
+        lj_metrics.gc_steps_finalize)
+    set_gauge('gc_allocated', 'Total amount of allocated memory',
+        lj_metrics.gc_allocated)
+    set_gauge('jit_trace_num', 'Amount of JIT traces',
+        lj_metrics.jit_trace_num)
+    set_gauge('gc_steps_sweep', 'Count of incremental GC steps (sweep state)',
+        lj_metrics.gc_steps_sweep)
+    set_gauge('jit_trace_abort', 'Overall number of abort traces',
+        lj_metrics.jit_trace_abort)
+    set_gauge('jit_mcode_size', 'Total size of all allocated machine code areas',
+        lj_metrics.jit_mcode_size)
+    set_gauge('gc_steps_propagate', 'Count of incremental GC steps (propagate state)',
+        lj_metrics.gc_steps_propagate)
+    set_gauge('gc_steps_pause', 'Count of incremental GC steps (pause state)',
+        lj_metrics.gc_steps_pause)
+end
+
+local update = function() end
+
+if has_mics_module and misc.getmetrics ~= nil then
+    update = update_lj_metrics
+end
+
+return {
+    update = update,
+}

rpm/tarantool-metrics.spec

@@ -49,6 +49,7 @@ cp -rv cartridge %{br_luapkgdir}
      %{luapkgdir}/metrics/default_metrics/tarantool/fibers.lua
      %{luapkgdir}/metrics/default_metrics/tarantool/info.lua
      %{luapkgdir}/metrics/default_metrics/tarantool/init.lua
+     %{luapkgdir}/metrics/default_metrics/tarantool/luajit.lua
      %{luapkgdir}/metrics/default_metrics/tarantool/memory.lua
      %{luapkgdir}/metrics/default_metrics/tarantool/network.lua
      %{luapkgdir}/metrics/default_metrics/tarantool/operations.lua