> From CR: > The useful/general BasicHashtable uses a block allocation scheme to > reportedly reduce fragmentation. When the StringTable and SymbolTable used to > use this hashtable, performance benefits were reportedly observed because of > the block allocation scheme. Since these tables were moved to the concurrent > hashtables, the tables left that use the block allocation scheme are: > > AdapterHandlerLibrary, ResolutionError, LoaderConstraints, Leak profiler > bitset table and Placeholders. 3 of these tables are very small and never > needed block allocation to prevent fragmentation at least. Also there are 3 > KVHashtables, which are built from BasicHashtable. 2 are used during dumping > and 1 is ID2KlassTable which appears small. > > ModuleEntry, PackageEntry, Dictionary, G1RootSet for nmethods, and > JvmtiTagMap tables didn't use the block allocation scheme. > > Removing this removes 7 pointers per table, and for each ClassLoaderData, > which has 3 tables, removes 21 pointers. > > This change was performance tested on linux and windows. > > It was also tested with tier1-6.
Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision: Fix Hashtable constructor and comments. ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/3123/files - new: https://git.openjdk.java.net/jdk/pull/3123/files/328f72c5..7a0ad9ee Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3123&range=01 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3123&range=00-01 Stats: 20 lines in 2 files changed: 0 ins; 16 del; 4 mod Patch: https://git.openjdk.java.net/jdk/pull/3123.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/3123/head:pull/3123 PR: https://git.openjdk.java.net/jdk/pull/3123
