Use faster clock_gettime() instead of sysctl() to get current ticks on iOS10
BUG=724546
Review-Url: https://codereview.chromium.org/2894173002
Cr-Commit-Position: refs/heads/master@{#474336}
diff --git a/base/time/time_mac.cc b/base/time/time_mac.cc
index 0ae3a30..52800a83 100644
--- a/base/time/time_mac.cc
+++ b/base/time/time_mac.cc
@@ -23,6 +23,11 @@
#include "base/numerics/safe_conversions.h"
#include "build/build_config.h"
+#if defined(OS_IOS)
+#include <time.h>
+#include "base/ios/ios_util.h"
+#endif
+
namespace {
#if defined(OS_MACOSX) && !defined(OS_IOS)
@@ -52,8 +57,20 @@
}
#endif // defined(OS_MACOSX) && !defined(OS_IOS)
+// Returns monotonically growing number of ticks in microseconds since some
+// unspecified starting point.
int64_t ComputeCurrentTicks() {
#if defined(OS_IOS)
+ // iOS 10 supports clock_gettime(CLOCK_MONOTONIC, ...), which is
+ // around 15 times faster than sysctl() call. Use it if possible;
+ // otherwise, fall back to sysctl().
+ if (base::ios::IsRunningOnIOS10OrLater()) {
+ struct timespec tp;
+ if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0) {
+ return (int64_t)tp.tv_sec * 1000000 + tp.tv_nsec / 1000;
+ }
+ }
+
// On iOS mach_absolute_time stops while the device is sleeping. Instead use
// now - KERN_BOOTTIME to get a time difference that is not impacted by clock
// changes. KERN_BOOTTIME will be updated by the system whenever the system
diff --git a/net/quic/platform/impl/quic_chromium_clock.cc b/net/quic/platform/impl/quic_chromium_clock.cc
index fb591f84..78ca26e 100644
--- a/net/quic/platform/impl/quic_chromium_clock.cc
+++ b/net/quic/platform/impl/quic_chromium_clock.cc
@@ -4,12 +4,6 @@
#include "net/quic/platform/impl/quic_chromium_clock.h"
-#if defined(OS_IOS)
-#include <time.h>
-
-#include "base/ios/ios_util.h"
-#endif
-
#include "base/memory/singleton.h"
#include "base/time/time.h"
@@ -29,21 +23,17 @@
}
QuicTime QuicChromiumClock::Now() const {
-#if defined(OS_IOS)
- if (base::ios::IsRunningOnIOS10OrLater()) {
- struct timespec tp;
- if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0) {
- return CreateTimeFromMicroseconds(tp.tv_sec * 1000000 +
- tp.tv_nsec / 1000);
- }
- }
-#endif
- return CreateTimeFromMicroseconds(base::TimeTicks::Now().ToInternalValue());
+ int64_t ticks = (base::TimeTicks::Now() - base::TimeTicks()).InMicroseconds();
+ DCHECK_GE(ticks, 0);
+ return CreateTimeFromMicroseconds(ticks);
}
QuicWallTime QuicChromiumClock::WallNow() const {
- return QuicWallTime::FromUNIXMicroseconds(base::Time::Now().ToJavaTime() *
- 1000);
+ const base::TimeDelta time_since_unix_epoch =
+ base::Time::Now() - base::Time::UnixEpoch();
+ int64_t time_since_unix_epoch_micro = time_since_unix_epoch.InMicroseconds();
+ DCHECK_GE(time_since_unix_epoch_micro, 0);
+ return QuicWallTime::FromUNIXMicroseconds(time_since_unix_epoch_micro);
}
} // namespace net
