Add support for ittapi measurement

Project.toml

@@ -1,3 +1,4 @@
 [deps]
 DocOpt = "968ba79b-81e4-546f-ab3a-2eecfa62a9db"
+JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
 PrettyTables = "08abe8d2-0d0c-5749-adfa-8a2ac140af0d"

lib/Makefile

@@ -0,0 +1,4 @@
+VTUNE_DIR := /opt/intel/oneapi/vtune/latest
+
+itt.so: itt.c
+	gcc -shared -fPIC $< -I$(VTUNE_DIR)/include -L$(VTUNE_DIR)/lib64 -l:libittnotify.a -o $@

lib/itt.c

@@ -0,0 +1,17 @@
+#include <ittnotify.h>
+
+__itt_domain* gc_domain = 0;
+__itt_string_handle* handle_main = 0;
+
+void init() {
+    gc_domain = __itt_domain_create("org.julialang.gc");
+    handle_main = __itt_string_handle_create("collect");
+}
+
+void gc_begin() {
+    __itt_task_begin(gc_domain, __itt_null, __itt_null, handle_main);
+}
+
+void gc_end() {
+    __itt_task_end(gc_domain);
+}

utils.jl

@@ -2,6 +2,24 @@ using Pkg
 Pkg.instantiate() # It is dumb that I have to do this
 using Serialization
 
+module ITT
+    import Libdl
+    const GC_LIB = joinpath(@__DIR__, "lib/itt.so")
+
+    function __init__()
+        lib = Libdl.dlopen(GC_LIB)
+        sym_init = Libdl.dlsym(lib, :init)
+        sym_begin = Libdl.dlsym(lib, :gc_begin)
+        sym_end = Libdl.dlsym(lib, :gc_end)
+
+        ccall(sym_init, Cvoid, ())
+        ccall(:jl_gc_set_cb_pre_gc, Cvoid, (Ptr{Cvoid}, Cint),
+                sym_begin, true)
+        ccall(:jl_gc_set_cb_post_gc, Cvoid, (Ptr{Cvoid}, Cint),
+                sym_end, true)
+    end
+end
+
 macro gctime(ex)
     fc = isdefined(Base.Experimental, Symbol("@force_compile")) ?
         :(Base.Experimental.@force_compile) :