Warn when emulator is not optimised (#40)

Warn when emulator is not optimised

Supported with OTP24 and above.

src/erlperf.erl

@@ -163,6 +163,10 @@
 -type system_information() :: #{
     os := {unix | win32, atom()},
     system_version := string(),
+    debug => boolean(),     %% true if the emulator has been debug-compiled, otherwise false
+    emu_type => atom(),     %% see system_info(emu_type), since OTP 24
+    emu_flavor => atom(),   %% see system_info(emu_flavor), since OTP 24
+    dynamic_trace => atom(),%% see system_info(dynamic_trace), since OTP 24
     cpu => string()
 }.
 %% System information, as returned by {@link erlang:system_info/1}
@@ -779,14 +783,21 @@ report_stats(Samples) ->
 
 system_report() ->
     OSType = erlang:system_info(os_type),
-    Guaranteed = #{
+    Guaranteed = detect_feature([emu_type, emu_flavor, dynamic_trace], #{
         os => OSType,
         system_version => string:trim(erlang:system_info(system_version), trailing)
-    },
+    }),
     try Guaranteed#{cpu => string:trim(detect_cpu(OSType), both)}
     catch _:_ -> Guaranteed
     end.
 
+detect_feature([], System) ->
+    System;
+detect_feature([F | T], System) ->
+    try detect_feature(T, System#{F => erlang:system_info(F)})
+    catch error:badarg -> detect_feature(T, System)
+    end.
+
 detect_cpu({unix, freebsd}) ->
     os:cmd("sysctl -n hw.model");
 detect_cpu({unix, darwin}) ->

src/erlperf_cli.erl

@@ -372,23 +372,23 @@ color(info, Text) -> Text.
 
 %% Report formatter
 format_report(full, [#{system := System} | _] = Reports, Width) ->
-    [format_system(System), format_report(extended, Reports, Width)];
+    warn_system(System) ++ [format_system(System), format_report(extended, Reports, Width)];
 
-format_report(extended, Reports, Width) ->
+format_report(extended, [#{system := System} | _] = Reports, Width) ->
     Sorted = sort_by(Reports),
     #{result := #{average := MaxAvg}} = hd(Sorted),
     Header = ["Code", "   ||", "  Samples", "      Avg", "  StdDev", "   Median", "     P99", " Iteration", "   Rel"],
     Data = [format_report_line(MaxAvg, ReportLine, extended) || ReportLine <- Sorted],
-    format_table(remove_relative_column([Header | Data]), Width);
+    warn_system(System) ++ format_table(remove_relative_column([Header | Data]), Width);
 
-format_report(basic, Reports, Width) ->
+format_report(basic, [#{system := System} | _] = Reports, Width) ->
     Sorted = sort_by(Reports),
     #{result := #{average := MaxAvg}} = hd(Sorted),
     Header = ["Code", "       ||", "       QPS", "      Time", "  Rel"],
     Data0 = [format_report_line(MaxAvg, ReportLine, basic) || ReportLine <- Sorted],
     %% remove columns that should not be displayed in basic mode
     Data = [[C1, C2, C3, C4, C5] || [C1, C2, _, C3, _, _, _, C4, C5] <- Data0],
-    format_table(remove_relative_column([Header | Data]), Width).
+    warn_system(System) ++ format_table(remove_relative_column([Header | Data]), Width).
 
 sort_by([#{mode := timed} | _] = Reports) ->
     lists:sort(fun (#{result := #{average := L}}, #{result := #{average := R}}) -> L < R end, Reports);
@@ -475,6 +475,15 @@ format_code(Code) when is_list(Code) ->
 format_code(Code) when is_binary(Code) ->
     binary_to_list(Code).
 
+warn_system(#{dynamic_trace := Trace} = System) when Trace =/= none ->
+    [io_lib:format("WARNING: Dynamic Trace Probes enabled (~s detected)~n", [Trace]) | warn_system(maps:remove(dynamic_trace, System))];
+warn_system(#{emu_type := Type} = System) when Type =/= opt ->
+    [io_lib:format("WARNING: Emulator is not optimised (~s detected)~n", [Type]) | warn_system(maps:remove(emu_type, System))];
+warn_system(#{emu_flavor := Flavor} = System) when Flavor =/= jit ->
+    [io_lib:format("WARNING: Emulator is not JIT (~s detected)~n", [Flavor]) | warn_system(maps:remove(emu_flavor, System))];
+warn_system(_) ->
+    [].
+
 format_system(#{os := OSType, system_version := SystemVsn} = System) ->
     OS = io_lib:format("OS : ~s~n", [format_os(OSType)]),
     CPU = if is_map_key(cpu, System) -> io_lib:format("CPU: ~s~n", [maps:get(cpu, System)]); true -> "" end,