[Tarantool-patches] [PATCH 2/2] metrics: add C and Lua API

[Sergey Kaplun <skaplun@tarantool.org>]

This patch adds C and Lua API for luajit metrics. Metrics include GC
statistic, JIT information, strhash hit/miss counters and amount of
different objects. C API provides with aditional header <lmisclib.h>
that contains structure `luam_metrics` and `luaM_metrics` function
definition. Lua userspace expanded with builtin library (named `misc`)
with corresponding method `getmetrics`. Metrics are divided by the two
types: global and incremental. Global metrics are collected throughout
the platform uptime. Incremental metrics are reset after each
`luaM_metrics()` call.

Part of tarantool/tarantool#5187
---
 Makefile           |  2 +-
 src/Makefile       |  5 +--
 src/Makefile.dep   |  3 ++
 src/lib_init.c     |  2 ++
 src/lib_misc.c     | 89 ++++++++++++++++++++++++++++++++++++++++++++++
 src/lj_misc_capi.c | 82 ++++++++++++++++++++++++++++++++++++++++++
 src/lmisclib.h     | 71 ++++++++++++++++++++++++++++++++++++
 src/luaconf.h      |  1 +
 8 files changed, 252 insertions(+), 3 deletions(-)
 create mode 100644 src/lib_misc.c
 create mode 100644 src/lj_misc_capi.c
 create mode 100644 src/lmisclib.h

diff --git a/Makefile b/Makefile
index 0f93308..4a56917 100644
--- a/Makefile
+++ b/Makefile
@@ -84,7 +84,7 @@ FILE_A= libluajit.a
 FILE_SO= libluajit.so
 FILE_MAN= luajit.1
 FILE_PC= luajit.pc
-FILES_INC= lua.h lualib.h lauxlib.h luaconf.h lua.hpp luajit.h
+FILES_INC= lua.h lualib.h lauxlib.h luaconf.h lua.hpp luajit.h lmisclib.h
 FILES_JITLIB= bc.lua bcsave.lua dump.lua p.lua v.lua zone.lua \
 	      dis_x86.lua dis_x64.lua dis_arm.lua dis_arm64.lua \
 	      dis_arm64be.lua dis_ppc.lua dis_mips.lua dis_mipsel.lua \
diff --git a/src/Makefile b/src/Makefile
index 827d4a4..fac69bc 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -480,13 +480,14 @@ LJVM_BOUT= $(LJVM_S)
 LJVM_MODE= elfasm
 
 LJLIB_O= lib_base.o lib_math.o lib_bit.o lib_string.o lib_table.o \
-	 lib_io.o lib_os.o lib_package.o lib_debug.o lib_jit.o lib_ffi.o
+	 lib_io.o lib_os.o lib_package.o lib_debug.o lib_jit.o lib_ffi.o \
+	 lib_misc.o
 LJLIB_C= $(LJLIB_O:.o=.c)
 
 LJCORE_O= lj_gc.o lj_err.o lj_char.o lj_bc.o lj_obj.o lj_buf.o \
 	  lj_str.o lj_tab.o lj_func.o lj_udata.o lj_meta.o lj_debug.o \
 	  lj_state.o lj_dispatch.o lj_vmevent.o lj_vmmath.o lj_strscan.o \
-	  lj_strfmt.o lj_strfmt_num.o lj_api.o lj_profile.o \
+	  lj_strfmt.o lj_strfmt_num.o lj_api.o lj_misc_capi.o lj_profile.o \
 	  lj_lex.o lj_parse.o lj_bcread.o lj_bcwrite.o lj_load.o \
 	  lj_ir.o lj_opt_mem.o lj_opt_fold.o lj_opt_narrow.o \
 	  lj_opt_dce.o lj_opt_loop.o lj_opt_split.o lj_opt_sink.o \
diff --git a/src/Makefile.dep b/src/Makefile.dep
index 2b1cb5e..1c3d8bd 100644
--- a/src/Makefile.dep
+++ b/src/Makefile.dep
@@ -41,6 +41,9 @@ lib_string.o: lib_string.c lua.h luaconf.h lauxlib.h lualib.h lj_obj.h \
 lib_table.o: lib_table.c lua.h luaconf.h lauxlib.h lualib.h lj_obj.h \
  lj_def.h lj_arch.h lj_gc.h lj_err.h lj_errmsg.h lj_buf.h lj_str.h \
  lj_tab.h lj_ff.h lj_ffdef.h lj_lib.h lj_libdef.h
+lib_misc.o: lib_misc.c lua.h lmisclib.h luaconf.h lj_obj.h lj_tab.h lj_str.h \
+ lj_arch.h lj_lib.h lj_vm.h lj_libdef.h
+lj_misc_capi.o: lj_misc_capi.c lua.h lmisclib.h luaconf.h lj_obj.h lj_arch.h
 lj_alloc.o: lj_alloc.c lj_def.h lua.h luaconf.h lj_arch.h lj_alloc.h
 lj_api.o: lj_api.c lj_obj.h lua.h luaconf.h lj_def.h lj_arch.h lj_gc.h \
  lj_err.h lj_errmsg.h lj_debug.h lj_str.h lj_tab.h lj_func.h lj_udata.h \
diff --git a/src/lib_init.c b/src/lib_init.c
index 2ed370e..664aa7d 100644
--- a/src/lib_init.c
+++ b/src/lib_init.c
@@ -12,6 +12,7 @@
 #include "lua.h"
 #include "lauxlib.h"
 #include "lualib.h"
+#include "lmisclib.h"
 
 #include "lj_arch.h"
 
@@ -26,6 +27,7 @@ static const luaL_Reg lj_lib_load[] = {
   { LUA_DBLIBNAME,	luaopen_debug },
   { LUA_BITLIBNAME,	luaopen_bit },
   { LUA_JITLIBNAME,	luaopen_jit },
+  { LUAM_MISCLIBNAME,	luaopen_misc },
   { NULL,		NULL }
 };
 
diff --git a/src/lib_misc.c b/src/lib_misc.c
new file mode 100644
index 0000000..d23c2db
--- /dev/null
+++ b/src/lib_misc.c
@@ -0,0 +1,89 @@
+/*
+ * Lua interface to tarantool-specific extensions to the public Lua/C API.
+ *
+ * Major portions taken verbatim or adapted from the LuaVela interpreter.
+ * Copyright (C) 2015-2019 IPONWEB Ltd.
+*/
+
+#define lib_misc_c
+#define LUA_LIB
+
+#include "lua.h"
+#include "lmisclib.h"
+
+#include "lj_obj.h"
+#include "lj_str.h"
+#include "lj_tab.h"
+#include "lj_ff.h"
+#include "lj_lib.h"
+
+/* ------------------------------------------------------------------------ */
+
+static LJ_AINLINE void setnumfield(struct lua_State *L, GCtab *t,
+				   const char *name, int64_t val)
+{
+	GCstr *key = lj_str_new(L, name, strlen(name));
+	setnumV(lj_tab_setstr(L, t, key), (double)val);
+}
+
+static LJ_AINLINE void settabfield(struct lua_State *L, GCtab *t,
+				   const char *name, GCtab *val)
+{
+	GCstr *key = lj_str_new(L, name, strlen(name));
+	settabV(L, lj_tab_setstr(L, t, key), val);
+}
+
+#define LJLIB_MODULE_misc
+
+LJLIB_CF(misc_getmetrics)
+{
+	lua_createtable(L, 0, 7);
+	GCtab *glob_m = tabV(L->top - 1);
+	lua_createtable(L, 0, 12);
+	GCtab *inc_m = tabV(L->top - 1);
+	lua_createtable(L, 0, 2);
+	GCtab *m = tabV(L->top - 1);
+
+	struct luam_Metrics metrics;
+	luaM_metrics(L, &metrics);
+
+	setnumfield(L, glob_m, "strnum", metrics.strnum);
+	setnumfield(L, glob_m, "tabnum", metrics.tabnum);
+	setnumfield(L, glob_m, "udatanum", metrics.udatanum);
+	setnumfield(L, glob_m, "cdatanum", metrics.cdatanum);
+
+	setnumfield(L, glob_m, "gc_total", metrics.gc_total);
+
+	setnumfield(L, glob_m, "jit_mcode_size", metrics.jit_mcode_size);
+	setnumfield(L, glob_m, "jit_trace_num", metrics.jit_trace_num);
+
+	setnumfield(L, inc_m, "gc_freed", metrics.gc_freed);
+	setnumfield(L, inc_m, "gc_allocated", metrics.gc_allocated);
+
+	setnumfield(L, inc_m, "gc_steps_pause", metrics.gc_steps_pause);
+	setnumfield(L, inc_m, "gc_steps_propagate", metrics.gc_steps_propagate);
+	setnumfield(L, inc_m, "gc_steps_atomic", metrics.gc_steps_atomic);
+	setnumfield(L, inc_m, "gc_steps_sweepstring",
+		    metrics.gc_steps_sweepstring);
+	setnumfield(L, inc_m, "gc_steps_sweep", metrics.gc_steps_sweep);
+	setnumfield(L, inc_m, "gc_steps_finalize", metrics.gc_steps_finalize);
+
+	setnumfield(L, inc_m, "jit_snap_restore", metrics.jit_snap_restore);
+	setnumfield(L, inc_m, "jit_trace_abort", metrics.jit_trace_abort);
+
+	setnumfield(L, inc_m, "strhash_hit", metrics.strhash_hit);
+	setnumfield(L, inc_m, "strhash_miss", metrics.strhash_miss);
+	settabfield(L, m, "global", glob_m);
+	settabfield(L, m, "incremental", inc_m);
+	return 1;
+}
+
+/* ------------------------------------------------------------------------ */
+
+#include "lj_libdef.h"
+
+LUALIB_API int luaopen_misc(struct lua_State *L)
+{
+	LJ_LIB_REG(L, LUAM_MISCLIBNAME, misc);
+	return 1;
+}
diff --git a/src/lj_misc_capi.c b/src/lj_misc_capi.c
new file mode 100644
index 0000000..5f99064
--- /dev/null
+++ b/src/lj_misc_capi.c
@@ -0,0 +1,82 @@
+/*
+** Tarantool-specific extensions to the public Lua/C API.
+**
+** Major portions taken verbatim or adapted from the LuaVela.
+** Copyright (C) 2015-2019 IPONWEB Ltd.
+*/
+
+#include "lua.h"
+#include "lmisclib.h"
+
+#include "lj_obj.h"
+#include "lj_gc.h"
+#include "lj_dispatch.h"
+
+#if LJ_HASJIT
+#include "lj_jit.h"
+#endif
+
+LUAM_API struct luam_Metrics *
+luaM_metrics(lua_State *L, struct luam_Metrics *dst)
+{
+	memset(dst, 0, sizeof(*dst));
+	global_State *g = G(L);
+	GCState *gc = &g->gc;
+#if LJ_HASJIT
+	jit_State *J = G2J(g);
+#endif
+
+	dst->strhash_hit = g->strhash_hit;
+	g->strhash_hit = 0;
+	dst->strhash_miss = g->strhash_miss;
+	g->strhash_miss = 0;
+
+	dst->strnum = g->strnum;
+	dst->tabnum = gc->tabnum;
+	dst->udatanum = gc->udatanum;
+#if LJ_HASFFI
+	dst->cdatanum = gc->cdatanum;
+#else
+	dst->cdatanum = 0;
+#endif
+
+	dst->gc_total = gc->total;
+	dst->gc_freed = gc->freed;
+	gc->freed = 0;
+	dst->gc_allocated = gc->allocated;
+	gc->allocated = 0;
+
+	dst->gc_steps_pause = gc->state_count[GCSpause];
+	gc->state_count[GCSpause] = 0;
+
+	dst->gc_steps_propagate = gc->state_count[GCSpropagate];
+	gc->state_count[GCSpropagate] = 0;
+
+	dst->gc_steps_atomic = gc->state_count[GCSatomic];
+	gc->state_count[GCSatomic] = 0;
+
+	dst->gc_steps_sweepstring = gc->state_count[GCSsweepstring];
+	gc->state_count[GCSsweepstring] = 0;
+
+	dst->gc_steps_sweep = gc->state_count[GCSsweep];
+	gc->state_count[GCSsweep] = 0;
+
+	dst->gc_steps_finalize = gc->state_count[GCSfinalize];
+	gc->state_count[GCSfinalize] = 0;
+
+#if LJ_HASJIT
+	dst->jit_snap_restore = J->nsnaprestore;
+	J->nsnaprestore = 0;
+	dst->jit_trace_abort = J->ntraceabort;
+	J->ntraceabort = 0;
+
+	dst->jit_mcode_size = J->szallmcarea;
+	dst->jit_trace_num = J->freetrace;
+#else
+	dst->jit_snap_restore = 0;
+	dst->jit_mcode_size = 0;
+	dst->jit_trace_num = 0;
+#endif
+
+	return dst;
+}
diff --git a/src/lmisclib.h b/src/lmisclib.h
new file mode 100644
index 0000000..8d63038
--- /dev/null
+++ b/src/lmisclib.h
@@ -0,0 +1,71 @@
+/*
+ * Major portions taken verbatim or adapted from the LuaVela.
+ * Copyright (C) 2015-2019 IPONWEB Ltd.
+ */
+
+#ifndef _LMISCLIB_H_INCLUDED
+#define _LMISCLIB_H_INCLUDED
+
+#include "lua.h"
+
+/* API for obtaining various metrics from the platform. */
+
+struct luam_Metrics {
+	/*
+	 * New string has been found in the storage since last
+	 * luaM_metrics() call.
+	 */
+	size_t strhash_hit;
+	/*
+	 * New string has been added to the storage since last
+	 * luaM_metrics() call.
+	 */
+	size_t strhash_miss;
+
+	size_t strnum;   /* Current amount of string objects. */
+	size_t tabnum;   /* Current amount of table objects. */
+	size_t udatanum; /* Current amount of udata objects. */
+	size_t cdatanum; /* Current amount of cdata objects. */
+
+	/* Memory currently allocated. */
+	size_t gc_total;
+	/* Memory freed since last luaM_metrics() call. */
+	size_t gc_freed;
+	/* Memory allocated since last luaM_metrics() call. */
+	size_t gc_allocated;
+
+	/*
+	 * Count of GC invocations with different states
+	 * since previous call of luaM_metrics().
+	 */
+	size_t gc_steps_pause;
+	size_t gc_steps_propagate;
+	size_t gc_steps_atomic;
+	size_t gc_steps_sweepstring;
+	size_t gc_steps_sweep;
+	size_t gc_steps_finalize;
+
+	/*
+	 * Overall number of snap restores for all traces
+	 * "belonging" to the given jit_State since the last call
+	 * to luaM_metrics().
+	 */
+	size_t jit_snap_restore;
+	/*
+	 * Overall number of abort traces "belonging" to the given
+	 * jit_State since the last call to luaM_metrics().
+	 */
+	size_t jit_trace_abort;
+	/* Total size of all allocated machine code areas. */
+	size_t jit_mcode_size;
+	/* Current amount of JIT traces. */
+	unsigned int jit_trace_num;
+};
+
+LUAM_API struct luam_Metrics *luaM_metrics(lua_State *L,
+					   struct luam_Metrics *dst);
+
+#define LUAM_MISCLIBNAME "misc"
+LUALIB_API int luaopen_misc(lua_State *L);
+
+#endif /* _LMISCLIB_H_INCLUDED */
diff --git a/src/luaconf.h b/src/luaconf.h
index 60cb928..cf01e36 100644
--- a/src/luaconf.h
+++ b/src/luaconf.h
@@ -144,6 +144,7 @@
 #endif
 
 #define LUALIB_API	LUA_API
+#define LUAM_API	LUA_API
 
 /* Support for internal assertions. */
 #if defined(LUA_USE_ASSERT) || defined(LUA_USE_APICHECK)
-- 
2.24.1