[perf] Use load average limit only during buck analysis

Reviewed By: jberdine

Differential Revision: D4146841

fbshipit-source-id: 026d25c

infer/src/backend/infer.ml

@@ -142,7 +142,7 @@ let capture build_cmd build_mode =
     (if not Config.flavors || not in_buck_mode || is_analyze_cmd build_cmd then [] else
        ["--use-flavors"]) @
     "-j" :: (string_of_int Config.jobs) ::
-    "-l" :: (string_of_float Config.load_average) ::
+    (Option.map_default (fun l -> ["-l"; string_of_float l]) [] Config.load_average) @
     (if not Config.pmd_xml then [] else
        ["--pmd-xml"]) @
     ["--project-root"; Config.project_root] @

infer/src/base/CommandLineOption.ml

@@ -314,6 +314,11 @@ let mk_float ~default ?(deprecated=[]) ~long ?short ?exes ?(meta="") doc =
     ~decode_json:(string_json_decoder ~long)
     ~mk_spec:(fun set -> Arg.String set)
 
+let mk_float_opt ?default ?(deprecated=[]) ~long ?short ?exes ?(meta="") doc =
+  let default_to_string = function Some f -> string_of_float f | None -> "" in
+  let f s = Some (float_of_string s) in
+  mk_option ~deprecated ~long ?short ~default ~default_to_string ~f ?exes ~meta doc
+
 let mk_string ~default ?(f=fun s -> s) ?(deprecated=[]) ~long ?short ?exes ?(meta="") doc =
   mk ~deprecated ~long ?short ~default ?exes ~meta doc
     ~default_to_string:(fun s -> s)

infer/src/base/CommandLineOption.mli

@@ -64,6 +64,8 @@ val mk_int : default:int -> int ref t
 
 val mk_float : default:float -> float ref t
 
+val mk_float_opt : ?default:float -> float option ref t
+
 val mk_string : default:string -> ?f:(string -> string) -> string ref t
 
 val mk_string_opt : ?default:string -> ?f:(string -> string) -> string option ref t

infer/src/base/Config.ml

@@ -955,7 +955,7 @@ and linters_def_file =
     ~meta:"file" "Specify the file containing linters definition"
 
 and load_average =
-  CLOpt.mk_float ~long:"load-average" ~short:"l" ~default:(float_of_int ncpu)
+  CLOpt.mk_float_opt ~long:"load-average" ~short:"l"
     ~exes:CLOpt.[Toplevel] ~meta:"float"
     "Do not start new parallel jobs if the load average is greater than that specified (Buck and \
      make only)"
@@ -1444,7 +1444,11 @@ and jobs = !jobs
 and join_cond = !join_cond
 and latex = !latex
 and linters_def_file = !linters_def_file
-and load_average = !load_average
+and load_average = match !load_average with
+  | None when !buck ->
+      Some (float_of_int ncpu)
+  | _ ->
+      !load_average
 and load_analysis_results = !load_results
 and makefile_cmdline = !makefile
 and merge = !merge

infer/src/base/Config.mli

@@ -81,7 +81,7 @@ val ivar_attributes : string
 val lib_dir : string
 val lint_dotty_dir_name : string
 val lint_issues_dir_name : string
-val load_average : float
+val load_average : float option
 val log_analysis_crash : string
 val log_analysis_file : string
 val log_analysis_procedure : string