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2010-09-08Re-enable spin wait on ethreads rwlocksRickard Green
Spin wait on most ethread rwlocks used by the runtime system was unintentionally disabled during development. Spin wait has now been enabled again. This bug appeared in commit 59ee2a593090e7d53c97ceba63cbd300d1b9657e, i.e., it has not been seen in any released versions.
2010-08-10Rewrite ethread libraryRickard Green
Large parts of the ethread library have been rewritten. The ethread library is an Erlang runtime system internal, portable thread library used by the runtime system itself. Most notable improvement is a reader optimized rwlock implementation which dramatically improve the performance of read-lock/read-unlock operations on multi processor systems by avoiding ping-ponging of the rwlock cache lines. The reader optimized rwlock implementation is used by miscellaneous rwlocks in the runtime system that are known to be read-locked frequently, and can be enabled on ETS tables by passing the `{read_concurrency, true}' option upon table creation. See the documentation of `ets:new/2' for more information. The ethread library can now also use the libatomic_ops library for atomic memory accesses. This makes it possible for the Erlang runtime system to utilize optimized atomic operations on more platforms than before. Use the `--with-libatomic_ops=PATH' configure command line argument when specifying where the libatomic_ops installation is located. The libatomic_ops library can be downloaded from: http://www.hpl.hp.com/research/linux/atomic_ops/ The changed API of the ethread library has also caused modifications in the Erlang runtime system. Preparations for the to come "delayed deallocation" feature has also been done since it depends on the ethread library. Note: When building for x86, the ethread library will now use instructions that first appeared on the pentium 4 processor. If you want the runtime system to be compatible with older processors (back to 486) you need to pass the `--enable-ethread-pre-pentium4-compatibility' configure command line argument when configuring the system.
2010-02-03Merge branch 'jb/atom-table-size' into ccase/r13b04_devErlang/OTP
* jb/atom-table-size: Add the +t emulator option to change the maximum number of atoms OTP-8405 There is a new +t emulator option for changing the maximum number of atoms. (Thanks to Julien Barbot.)
2010-02-02Add the +t emulator option to change the maximum number of atomsJulien Barbot
It is now possible to increase or decrease the maximum number of atoms the VM can handle. The default value is 1048576 (1024*1024).
2009-11-20The R13B03 release.OTP_R13B03Erlang/OTP