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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2021-11-03 18:19:04 +0100 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2021-11-03 18:37:22 +0000 |
| commit | cfd016df1fba2a2a104f4cca705aa4357777986b (patch) | |
| tree | a0704332a5565aa06525c733d7e935dab7eb2451 /src/runtime/time_windows.h | |
| parent | d4e0e8e4a41e5e1e7d0359287a1015791ce778ed (diff) | |
| download | go-cfd016df1fba2a2a104f4cca705aa4357777986b.tar.xz | |
runtime: on windows, read nanotime with one instruction or issue barrier
On 64-bit, this is more efficient, and on ARM64, this prevents the time
from moving backwards due to the weaker memory model. On ARM32 due to
the weaker memory model, we issue a memory barrier.
Updates #48072.
Change-Id: If4695716c3039d8af14e14808af217f5c99fc93a
Reviewed-on: https://go-review.googlesource.com/c/go/+/361057
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/time_windows.h')
| -rw-r--r-- | src/runtime/time_windows.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/runtime/time_windows.h b/src/runtime/time_windows.h index cd16fd163b..7c2e65c328 100644 --- a/src/runtime/time_windows.h +++ b/src/runtime/time_windows.h @@ -9,6 +9,7 @@ // http://web.archive.org/web/20210411000829/https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/ // Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2. +// Or, on 64-bit, just read lo:hi1 all at once atomically. #define _INTERRUPT_TIME 0x7ffe0008 #define _SYSTEM_TIME 0x7ffe0014 #define time_lo 0 |