On 7/06/2020 4:54 am, Christoph Dreis wrote:

I've stumbled upon UseBsdPosixThreadCPUClocks that seems unused in the code.

I don't know what the process for already unused flags is.
E.g. if they need to be deprecated first or can be removed directly.

I've prepared two patches - one for each option:

===== REMOVAL PATCH =====
--- a/src/hotspot/os/bsd/globals_bsd.hpp Sat Jun 06 08:13:40 2020 +0000
+++ b/src/hotspot/os/bsd/globals_bsd.hpp Sat Jun 06 20:25:58 2020 +0200
@@ -40,11 +40,6 @@
                                                                                 \
   product(bool, UseOprofile, false, \
         "enable support for Oprofile profiler") \
- \
- /* NB: The default value of UseBsdPosixThreadCPUClocks may be */ \
- /* overridden in Arguments::parse_each_vm_init_arg. */ \
- product(bool, UseBsdPosixThreadCPUClocks, true, \
- "enable fast Bsd Posix clocks where available") \

===== DEPRECATION PATCH =====
--- a/src/hotspot/share/runtime/arguments.cpp Sat Jun 06 08:13:40 2020 +0000
+++ b/src/hotspot/share/runtime/arguments.cpp Sat Jun 06 20:48:05 2020 +0200
@@ -535,6 +535,7 @@
   { "PrintPreciseBiasedLockingStatistics", JDK_Version::jdk(15), JDK_Version::jdk(16), JDK_Version::jdk(17) },
   { "InitialBootClassLoaderMetaspaceSize", JDK_Version::jdk(15), JDK_Version::jdk(16), JDK_Version::jdk(17) },
   { "UseLargePagesInMetaspace", JDK_Version::jdk(15), JDK_Version::jdk(16), JDK_Version::jdk(17) },
+ { "UseBsdPosixThreadCPUClocks", JDK_Version::jdk(15), JDK_Version::jdk(16), JDK_Version::jdk(17) },

   // --- Deprecated alias flags (see also aliased_jvm_flags) - sorted by obsolete_in then expired_in:
   { "DefaultMaxRAMFraction", JDK_Version::jdk(8), JDK_Version::undefined(), JDK_Version::undefined() },