From 7d06388110e52357f6ec3742b2fcc11d4ac3aadc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Fri, 17 Apr 2015 11:51:36 +0200
Subject: kernel: Add instruction_count helper to erts_debug

---
 lib/kernel/src/erts_debug.erl | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

(limited to 'lib/kernel/src/erts_debug.erl')

diff --git a/lib/kernel/src/erts_debug.erl b/lib/kernel/src/erts_debug.erl
index 17bee06b5e..8f81fcf825 100644
--- a/lib/kernel/src/erts_debug.erl
+++ b/lib/kernel/src/erts_debug.erl
@@ -20,7 +20,7 @@
 
 %% Low-level debugging support. EXPERIMENTAL!
 
--export([size/1,df/1,df/2,df/3]).
+-export([size/1,df/1,df/2,df/3,ic/1]).
 
 %% This module contains the following *experimental* BIFs:
 %%   disassemble/1
@@ -114,6 +114,19 @@ get_internal_state(_) ->
 instructions() ->
     erlang:nif_error(undef).
 
+-spec ic(F) -> Result when
+      F :: function(),
+      Result :: term().
+
+ic(F) when is_function(F) ->
+    Is0 = erlang:system_info(instruction_counts),
+    R   = F(),
+    Is1 = erlang:system_info(instruction_counts),
+    Is  = lists:keysort(2,[{I,C1 - C0}||{{I,C1},{I,C0}} <- lists:zip(Is1,Is0)]),
+    _   = [io:format("~12w ~w~n", [C,I])||{I,C}<-Is],
+    io:format("Total: ~w~n",[lists:sum([C||{_I,C}<-Is])]),
+    R.
+
 -spec lock_counters(info) -> term();
                       (clear) -> ok;
                       ({copy_save, boolean()}) -> boolean();
-- 
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