DMTCP 1.2.4 released

DMTCP (Distributed MultiThreaded Checkpointing) is a tool to transparently checkpoint the state of multiple simultaneous applications, including multi-threaded and distributed applications. It operates directly on the user binary executable, without any Linux kernel modules or other kernel modifications.

Release Notes:
- There is now much more robust treatment of processes that rapidly create and destroy threads. This was the case for the Java JVM (both for OpenJDK and Oracle (Sun) Java). This was also the case for Cilk. Cilk++ was not tested. We believe this new DMTCP to now be highly robust -- and we would appreciate receiving a notification if you find a Java or Cilk program that is not compatible with DMTCP.
- Zero-mapped pages are no longer expanded and saved to the DMTCP checkpoint image. For Java programs (and other programs using zero-mapped pages for their allocation arena or garbage collecotr), the checkpoint image will now be much smaller. Checkpoint and restart times will also be faster.
- DMTCP_ROOT/dmtcp/doc directory added with documentation of some DMTCP internals. architecture-of-dmtcp.pdf is a good place to start reading for those who are curious.
- The directory of example modules was moved to DMTCP_ROOT/test/module. This continues to support third-part wrappers around system calls, can registering functions to be called by DMTCP at interesting times (like pre-checkpoint, post-resume, post-restart, new thread created, etc.).
- This version of MTCP (inside this package) should be compatible with the checkpoint-restart service of Open MPI. The usage will be documented soon through the Open MPI web site. As before, an alternative is to simply start Open MPI inside DMTCP, and let DMTCP treat all of Open MPI as a "black box" that happens to be a ditributed computation
- A new --prefix command line flag has been added to dmtcp_checkpoint. It operates similarly to the flag of the same name in Open MPI. For distributed computations, remote processes will use the prefix as part of the path to find the remote dmtcp_checkpoint command. This is useful when a gateway machine has a different directory structure from the remote nodes.
- configure --enable-ptrace-support now uses ptrace module (more modular code). The ptrace module should also be more robust. It now fixes some additional cases that were missing earlier
- ./configure --enable-unique-checkpoint-filenames was not respecting bin/dmtcp_checkpoint --checkpoint-open-files . This is now fixed.
- If the coordinator received a kill request in the middle of a checkpoint, the coordinator could freeze or die. This has now been fixed, with the expected behavior: Kill the old computation that is in the middle of a checkpoint, and then allow any new computations to begin.
- dmtcp_inspector utility was broken in last release; now fixed
- configure --enable-forked-checkpoint was broken in the last release. It is fixed again.
- Many smaller bug fixes.
- The debian packages and rpm packages for OpenSUSE will be submitted to the distros over the next few days.