File 0201-Speed-up-erts_debug-df.patch of Package erlang
From 79f28cfd8df1b700baff0df5e3d766d0a5592581 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Fri, 22 Sep 2017 07:24:51 +0200
Subject: [PATCH 1/2] Speed up erts_debug:df()
The test case erts_debug_SUITE:df/1 in the emulator test suite is
about 4 times faster with this change.
---
lib/kernel/src/erts_debug.erl | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/lib/kernel/src/erts_debug.erl b/lib/kernel/src/erts_debug.erl
index 480db6814e..2887014c1c 100644
--- a/lib/kernel/src/erts_debug.erl
+++ b/lib/kernel/src/erts_debug.erl
@@ -378,16 +378,11 @@ df(Mod, Func, Arity) when is_atom(Mod), is_atom(Func) ->
catch _:_ -> {undef,Mod}
end.
-dff(File, Fs) when is_pid(File), is_list(Fs) ->
- lists:foreach(fun(Mfa) ->
- disassemble_function(File, Mfa),
- io:nl(File)
- end, Fs);
-dff(Name, Fs) when is_list(Name) ->
- case file:open(Name, [write]) of
+dff(Name, Fs) ->
+ case file:open(Name, [write,raw,delayed_write]) of
{ok,F} ->
try
- dff(F, Fs)
+ dff_1(F, Fs)
after
_ = file:close(F)
end;
@@ -395,12 +390,18 @@ dff(Name, Fs) when is_list(Name) ->
{error,{badopen,Reason}}
end.
+dff_1(File, Fs) ->
+ lists:foreach(fun(Mfa) ->
+ disassemble_function(File, Mfa),
+ file:write(File, "\n")
+ end, Fs).
+
disassemble_function(File, {_,_,_}=MFA) ->
cont_dis(File, erts_debug:disassemble(MFA), MFA).
cont_dis(_, false, _) -> ok;
cont_dis(File, {Addr,Str,MFA}, MFA) ->
- io:put_chars(File, binary_to_list(Str)),
+ ok = file:write(File, Str),
cont_dis(File, erts_debug:disassemble(Addr), MFA);
cont_dis(_, {_,_,_}, _) -> ok.
--
2.14.1