On 26/05/2020 6:14 pm, Stephen Colebourne wrote:
AFAICT a nanosecond clock is fine from a java.time.* API perspective.
Thanks Stephen. Is this a review or just a nod of approval? :)
Cheers,
David
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Stephen
On Tue, 26 May 2020 at 06:01, David Holmes <[email protected]> wrote:
bug: https://bugs.openjdk.java.net/browse/JDK-8242504
webrev: http://cr.openjdk.java.net/~dholmes/8242504/webrev/
This work was contributed by Mark Kralj-Taylor:
https://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2020-April/038975.html
On the hotspot side we change the Linux implementations of
javaTimeMillis() and javaTimeSystemUTC() so that they use
clock_gettime(CLOCK_REALTIME) instead of gettimeofday(). In keeping with
our conditional use of this API I added a new guard
os::Posix::supports_clock_gettime()
and refined the existing supports_monotonic_clock() so that we can still
use CLOCK_REALTIME if CLOCK_MONOTONIC does not exist. In the future
(hopefully very near future) we will simply assume these APIs always exist.
On the core-libs side the existing test:
test/jdk/java/time/test/java/time/TestClock_System.java
is adjusted to track the precision in more detail.
Finally Mark has added instantNowAsEpochNanos() to the benchmark
previously known as
test/micro/org/openjdk/bench/java/lang/Systems.java
which I've renamed to SystemTime.java as Mark suggested. I agree having
these three functions measured together makes sense.
Testing:
- test/jdk/java/time/test/java/time/TestClock_System.java
- test/micro/org/openjdk/bench/java/lang/SystemTime.java
- Tiers 1-3
Thanks,
David
