Index: third_party/tcmalloc/chromium/src/base/spinlock_internal.cc |
=================================================================== |
--- third_party/tcmalloc/chromium/src/base/spinlock_internal.cc (revision 124832) |
+++ third_party/tcmalloc/chromium/src/base/spinlock_internal.cc (working copy) |
@@ -42,9 +42,6 @@ |
#include "base/spinlock_internal.h" |
-// forward declaration for use by spinlock_*-inl.h |
-namespace base { namespace internal { static int SuggestedDelayNS(int loop); }} |
- |
#if defined(_WIN32) |
#include "base/spinlock_win32-inl.h" |
#elif defined(__linux__) |
@@ -76,27 +73,5 @@ |
return v; |
} |
-// Return a suggested delay in nanoseconds for iteration number "loop" |
-static int SuggestedDelayNS(int loop) { |
- // Weak pseudo-random number generator to get some spread between threads |
- // when many are spinning. |
- static base::subtle::Atomic64 rand; |
- uint64 r = base::subtle::NoBarrier_Load(&rand); |
- r = 0x5deece66dLL * r + 0xb; // numbers from nrand48() |
- base::subtle::NoBarrier_Store(&rand, r); |
- |
- r <<= 16; // 48-bit random number now in top 48-bits. |
- if (loop < 0 || loop > 32) { // limit loop to 0..32 |
- loop = 32; |
- } |
- // loop>>3 cannot exceed 4 because loop cannot exceed 32. |
- // Select top 20..24 bits of lower 48 bits, |
- // giving approximately 0ms to 16ms. |
- // Mean is exponential in loop for first 32 iterations, then 8ms. |
- // The futex path multiplies this by 16, since we expect explicit wakeups |
- // almost always on that path. |
- return r >> (44 - (loop >> 3)); |
-} |
- |
} // namespace internal |
} // namespace base |