[scudo] Use getMonotonicTimeFast for tryLock.

cferris1000 · cferris1000 · commit 36ca9a29025a · 2023-06-29T13:07:08.000-07:00
In tryLock, the Precedence value is set using the fast time function now. This should speed up tryLock calls slightly. This should be okay even though the value is used as a kind of random value in getTSDAndLockSlow. The fast time call still sets enough bits to avoid getting the same TSD on every call. Reviewed By: Chia-hungDuan Differential Revision: https://reviews.llvm.org/D154039
diff --git a/compiler-rt/lib/scudo/standalone/tsd.h b/compiler-rt/lib/scudo/standalone/tsd.h
@@ -41,9 +41,9 @@ template <class Allocator> struct alignas(SCUDO_CACHE_LINE_SIZE) TSD {
       return true;
     }
     if (atomic_load_relaxed(&Precedence) == 0)
-      atomic_store_relaxed(
-          &Precedence,
-          static_cast<uptr>(getMonotonicTime() >> FIRST_32_SECOND_64(16, 0)));
+      atomic_store_relaxed(&Precedence,
+                           static_cast<uptr>(getMonotonicTimeFast() >>
+                                             FIRST_32_SECOND_64(16, 0)));
     return false;
   }
   inline void lock() NO_THREAD_SAFETY_ANALYSIS {

Original file line number	Diff line number	Diff line change
`@@ -41,9 +41,9 @@ template <class Allocator> struct alignas(SCUDO_CACHE_LINE_SIZE) TSD {`
`41`	`41`	`return true;`
`42`	`42`	`}`
`43`	`43`	`if (atomic_load_relaxed(&Precedence) == 0)`
`44`		`- atomic_store_relaxed(`
`45`		`- &Precedence,`
`46`		`- static_cast<uptr>(getMonotonicTime() >> FIRST_32_SECOND_64(16, 0)));`
	`44`	`+ atomic_store_relaxed(&Precedence,`
	`45`	`+ static_cast<uptr>(getMonotonicTimeFast() >>`
	`46`	`+ FIRST_32_SECOND_64(16, 0)));`
`47`	`47`	`return false;`
`48`	`48`	`}`
`49`	`49`	`inline void lock() NO_THREAD_SAFETY_ANALYSIS {`