Ignore iOS prewarming (oblador#97)

Author: oblador

examples/vanilla/ios/Podfile.lock

@@ -934,12 +934,21 @@ PODS:
   - react-native-flipper (0.182.0):
     - React-Core
   - react-native-performance (4.0.0):
-    - RCT-Folly
+    - hermes-engine
+    - RCT-Folly (= 2021.07.22.00)
     - RCTRequired
     - RCTTypeSafety
     - React-Codegen
     - React-Core
+    - React-debug
+    - React-Fabric
+    - React-graphics
+    - React-NativeModulesApple
+    - React-RCTFabric
+    - React-utils
+    - ReactCommon/turbomodule/bridging
     - ReactCommon/turbomodule/core
+    - Yoga
   - React-NativeModulesApple (0.72.1):
     - hermes-engine
     - React-callinvoker
@@ -1287,7 +1296,7 @@ SPEC CHECKSUMS:
   React-jsinspector: d0b5bfd1085599265f4212034321e829bdf83cc0
   React-logger: b8103c9b04e707b50cdd2b1aeb382483900cbb37
   react-native-flipper: 6e4e344a0104a34a4e189a9ef2b3b5634b516dc8
-  react-native-performance: 426cc34043381602a59f059755a04452315effb4
+  react-native-performance: 8d52c16b63aa3728464aa10a1e75dff23412ea2e
   React-NativeModulesApple: 4f31a812364443cee6ef768d256c594ad3b20f53
   React-perflogger: 3d501f34c8d4b10cb75f348e43591765788525ad
   React-RCTActionSheet: f5335572c979198c0c3daff67b07bd1ad8370c1d

packages/react-native-performance/ios/RNPerformanceManager.mm

@@ -9,21 +9,6 @@
 #import <RNPerformanceSpec/RNPerformanceSpec.h>
 #endif
 
-static CFTimeInterval RNPerformanceGetProcessStartTime()
-{
-    size_t len = 4;
-    int mib[len];
-    struct kinfo_proc kp;
-
-    sysctlnametomib("kern.proc.pid", mib, &len);
-    mib[3] = getpid();
-    len = sizeof(kp);
-    sysctl(mib, 4, &kp, &len, NULL, 0);
-
-    struct timeval startTime = kp.kp_proc.p_un.__p_starttime;
-    return startTime.tv_sec + startTime.tv_usec / 1e6;
-}
-
 static int64_t sNativeLaunchStart;
 static int64_t sNativeLaunchEnd;
 
@@ -38,8 +23,10 @@ @implementation RNPerformanceManager
 + (void) initialize
 {
     [super initialize];
-    sNativeLaunchStart = (RNPerformanceGetProcessStartTime() - [NSDate date].timeIntervalSince1970) * 1000 + RNPerformanceGetTimestamp();
+    struct timespec tp;
+    clock_gettime(CLOCK_THREAD_CPUTIME_ID, &tp);
     sNativeLaunchEnd = RNPerformanceGetTimestamp();
+    sNativeLaunchStart = sNativeLaunchEnd - (tp.tv_sec * 1e3 + tp.tv_nsec / 1e6);
 }
 
 - (void)setBridge:(RCTBridge *)bridge