> 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 pull request now contains ten commits: - Merge - 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. ------------- Changes: https://git.openjdk.java.net/jdk/pull/2090/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2090&range=03 Stats: 379 lines in 11 files changed: 54 ins; 299 del; 26 mod Patch: https://git.openjdk.java.net/jdk/pull/2090.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/2090/head:pull/2090 PR: https://git.openjdk.java.net/jdk/pull/2090
