From 3ea69369deed9f8e2c44bbdc72cb2a4d8a7bf0c3 Mon Sep 17 00:00:00 2001
From: Catherine Gasnier <catg@fb.com>
Date: Wed, 30 Sep 2020 08:16:20 -0700
Subject: [PATCH] only read counters when profile_log option is set

Summary: ... to avoid possibly expensive system calls

Differential Revision: D21740519

fbshipit-source-id: 0810f46acd834ef1fc1287bd33f39e8d90f47a03
---
 hphp/hack/src/typing/typing_check_service.ml | 46 ++++++++++++++++------------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/hphp/hack/src/typing/typing_check_service.ml b/hphp/hack/src/typing/typing_check_service.ml
index e06ec8da434..efaa0106a44 100644
--- a/hphp/hack/src/typing/typing_check_service.ml
+++ b/hphp/hack/src/typing/typing_check_service.ml
@@ -373,28 +373,34 @@ let process_files
       let (errors, deferred) =
         match fn with
         | Check file ->
-          let start_counters = read_counters () in
-          let result = process_file dynamic_view_files ctx errors file in
-          let end_counters = read_counters () in
-          let second_run_end_counters =
-            if check_info.profile_type_check_twice then
-              (* we're running this routine solely for the side effect *)
-              (* of seeing how long it takes to run. *)
-              let (_ignored : process_file_results) =
-                process_file dynamic_view_files ctx errors file
+          let process_file () =
+            process_file dynamic_view_files ctx errors file
+          in
+          let result =
+            if check_info.profile_log then (
+              let start_counters = read_counters () in
+              let result = process_file () in
+              let end_counters = read_counters () in
+              let second_run_end_counters =
+                if check_info.profile_type_check_twice then
+                  (* we're running this routine solely for the side effect *)
+                  (* of seeing how long it takes to run. *)
+                  let _ignored = process_file () in
+                  Some (read_counters ())
+                else
+                  None
               in
-              Some (read_counters ())
-            else
-              None
+              profile_log
+                ~check_info
+                ~start_counters
+                ~end_counters
+                ~second_run_end_counters
+                ~file
+                ~result;
+              result
+            ) else
+              process_file ()
           in
-          if check_info.profile_log then
-            profile_log
-              ~check_info
-              ~start_counters
-              ~end_counters
-              ~second_run_end_counters
-              ~file
-              ~result;
           (result.errors, result.computation)
         | Declare path ->
           let errors = Decl_service.decl_file ctx errors path in
-- 
2.11.4.GIT