Thanks for the reviews Erik and Magnus!
David
On 20/01/2021 12:26 am, Erik Joelsson wrote:
On Tue, 19 Jan 2021 01:53:03 GMT, David Holmes <dhol...@openjdk.org> wrote:
We are now confident that we have build-time and runtime support for
clock_gettime and CLOCK_MONOTONIC on all our OpenJDK supported POSIX platforms
- see bug report for some more details on different OS. Consequently we can
simplify a lot of the code in this area and move common code to os_posix.
As of glibc 2.17 the necessary functions are in glibc rather than librt, but we
(Oracle at least) aren't yet in position to set our minimum Linux version to
support that. We still have supported platforms at glibc 2.12. So to address
that we link librt at build time on Linux. This seems to work find for older
and more modern Linuxes and also works for the Apline Linux with Musl variant.
The changes are in layered commits:
Step 1: Remove build time checks. SUPPORTS_CLOCK_MONOTONIC is assumed true and
removed.
Step 2: make supports_monotonic_clock always true and so remove checking in OS
code
Step 3: Replace gettimeofday by clock_gettime(CLOCK_REALTIME)
Step 4: Move shared time functions to os_posix.cpp
Step 5: Alway link librt on Linux so we don't rely on glibc > 2.17
Testing: tiers 1-3 for functional testing
built and checked (-Xlog:os) on Linux with glibc 2.12 and 2.17,
macOS 10.13.6 and 10.15.7
David Holmes has updated the pull request with a new target base due to a merge
or a rebase. The incremental webrev excludes the unrelated changes brought in
by the merge/rebase. The pull request contains eight additional commits since
the last revision:
- Merge branch 'master' into 8246112-mono
- Restrict librt linking to JVM - per Magnus's request
- Merge branch 'master' into 8246112-mono
- Alway link librt on Linux so we don't rely on glibc > 2.12
- Step 4: Move shared time functions to os_posix.cpp
- Step 3: Replace gettimeofday by clock_gettime(CLOCK_REALTIME)
- Step 2: make supports_monotonic_clock always true and so remove checking it
(in OS code)
- 8246112: Remove build-time and run-time checks for clock_gettime and
CLOCK_MONOTONIC
Step 1: Remove build time checks. SUPPORTS_CLOCK_MONOTONIC is assumed true and removed.
Build changes look good to me.
-------------
Marked as reviewed by erikj (Reviewer).
PR: https://git.openjdk.java.net/jdk/pull/2090
