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authorBjörn Gustavsson <bjorn@erlang.org>2011-11-17 20:25:48 +0100
committerBjörn Gustavsson <bjorn@erlang.org>2011-11-23 10:40:33 +0100
commitad2962278f347a5d0341c0d5d11cbb71c83eb35b (patch)
tree13a15497b3f109a395fbabd7aa81ceb287b10c23
parentb3a8ad925c72bc77d3509ef8dce155d65dc1548b (diff)
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Avoid slow code loading of BEAM code in a hipe-enabled emulator
On my Linux computer, building the entire Erlang/OTP system with hipe disabled took about 8 minutes. With hipe enabled, but without any native code, the build took about 23 minutes, i.e. more than 3 times slower. (The computer has 4 cores, and I used 'make -j6'.) On my eight-core Mac (running 'make -j10') there was only a slight slowdown when hipe was enabled. The culprit is hipe_unified_loader:post_beam_load/1, which will be called every time a module is loaded (even if the module contains no native code). If post_beam_load/1 is called in a hipe-enabled emulator, it will block multi-scheduling, even if no work needs to be done. Apparently the cost for blocking multi-scheduling can vary greatly, depending on the operating system and system load. As a quick and conservative fix, don't call post_beam_load/1 unless some native code has been previously loaded.
-rw-r--r--lib/kernel/src/code_server.erl33
1 files changed, 26 insertions, 7 deletions
diff --git a/lib/kernel/src/code_server.erl b/lib/kernel/src/code_server.erl
index e3d22e7999..32a12e2b52 100644
--- a/lib/kernel/src/code_server.erl
+++ b/lib/kernel/src/code_server.erl
@@ -32,6 +32,8 @@
-import(lists, [foreach/2]).
+-define(ANY_NATIVE_CODE_LOADED, any_native_code_loaded).
+
-record(state, {supervisor,
root,
path,
@@ -97,6 +99,8 @@ init(Ref, Parent, [Root,Mode0]) ->
State0
end,
+ put(?ANY_NATIVE_CODE_LOADED, false),
+
Parent ! {Ref,{ok,self()}},
loop(State#state{supervisor = Parent}).
@@ -1278,20 +1282,35 @@ load_native_code(Mod, Bin) ->
%% Therefore we must test for that the loader modules are available
%% before trying to to load native code.
case erlang:module_loaded(hipe_unified_loader) of
- false -> no_native;
- true -> hipe_unified_loader:load_native_code(Mod, Bin)
+ false ->
+ no_native;
+ true ->
+ Result = hipe_unified_loader:load_native_code(Mod, Bin),
+ case Result of
+ {module,_} ->
+ put(?ANY_NATIVE_CODE_LOADED, true);
+ _ ->
+ ok
+ end,
+ Result
end.
hipe_result_to_status(Result) ->
case Result of
- {module,_} -> Result;
- _ -> {error,Result}
+ {module,_} ->
+ put(?ANY_NATIVE_CODE_LOADED, true),
+ Result;
+ _ ->
+ {error,Result}
end.
post_beam_load(Mod) ->
- case erlang:module_loaded(hipe_unified_loader) of
- false -> ok;
- true -> hipe_unified_loader:post_beam_load(Mod)
+ %% post_beam_load/1 can potentially be very expensive because it
+ %% blocks multi-scheduling; thus we want to avoid the call if we
+ %% know that it is not needed.
+ case get(?ANY_NATIVE_CODE_LOADED) of
+ true -> hipe_unified_loader:post_beam_load(Mod);
+ false -> ok
end.
int_list([H|T]) when is_integer(H) -> int_list(T);