The documentation for the public ALCF I/O Data Repository has been updated.  Please note that there is a new technical report that contains an updated description of the data and a suggested acknowledgement to include with publications that use the data.

Darshan 2.2.6 has been released.  This release includes performance enhancements as well as various minor bug fixes and compatibility improvements.
Changelog:
darshan-2.2.6

• Bug fixes:
  • make sure to honor user-specified hints passed in at runtime via the DARSHAN_LOGHINTS env variable.
  • include fread and fwrite in darshan-job-summary.pl read and write counts
  • fix segmentation fault on invalid arguments to darshan-parser
• Performance enhancements:
  • collect mount point information at rank 0 and broadcast to all
  • processes to avoid excess file system traffic on startup
  • change default MPI-IO hints for writing log file to romio_no_indep_rw=true and cb_nodes=4 to improve log creation performance
• Install libdarshan-util and headers during installation process for darshan-util; patch contributed by Matthieu Dorier
• Detect PMPI support at link time when using compiler scripts produced by the darshan-gen-* utilities. This avoids link problems when Darshan compiler wrappers are used with the ADIOS dummy MPI library; reported by Jingqing Mu
• Support MPICH_{CC/CXX/F77} environment variables in compiler scripts produced by the darshan-gen-* utilities
• Add instrumentation of startup time, enabled via DARSHAN_INTERNAL_TIMING environment variable
• Rename cp-shutdown-bench test utility to darshan-shutdown-bench and enable benchmarking hooks in library by default so that darshan-shutdown-bench can be used with any Darshan installation
• Remove deprecated –enable-st-dev-workaround configure option
• Misc. documentation updates

We will be presenting a new paper entitled “Production I/O Characterization on the Cray XE6” at this year’s CUG meeting, May 6-9, in Napa CA.  This presentation will include our experiences in evaluating and deploying Darshan on the Hopper system at NERSC.  We will also use data collected on Hopper to highlight example metrics to identify applications that can benefit from additional tuning.

Darshan version 2.2.5 has been released.  The  highlights of this release include multiple bug fixes and improvements to block size detection.  We would also like to thank Yushu Yao for contributing support for Cray xt-asyncpe 5.12 (and higher) environments.
Changelog:
Darshan 2.2.5

• Fix bug in mount point identification when –enable-stat-at-open option is not used. In Darshan 2.2.4, some file entries were recorded as using the “/” file system regardless of their location.
• Update patches and documentation for Cray xt-asyncpe environment 5.12 or higher; contributed by Yushu Yao.
• Update documentation to no longer recommend –enable-stat-at-open option on any systems
• Fix unresolved symbols error when linking non-MPI programs with Cray compiler. Reported by Yushu Yao.
• Use fstat() in place of stat() for detecting file information when –enable-stat-at-open option is used
• Use statfs() at startup to detect default block size for supported file systems
• Added –enable-group-readable-logs configure option, which will cause Darshan to to generate log files with the group read permission bit set. This option is useful in conjunction with deployments that set the setgid bit on log directories.

We have posted a new technical report entitled “Performance Analysis of Darshan 2.2.3 on the Cray XE6 Platform” to the Darshan publications page.  This report includes experimental results from the Beagle system at the University of Chicago Computation Institute.
Previous publications already investigated Darshan overhead on the IBM Blue Gene platform.  However, beginning with Darshan version 2.2.3 we fully support the Cray XE6 platform as well.  We used this opportunity to revisit the Darshan efficiency measurements and confirm that Darshan still operates with minimal impact to production applications.

Darshan 2.2.4 is now available on the download page.
If you are upgrading Darshan on a Cray platform, please re-patch your compiler scripts.  If you are upgrading Darshan on a Blue Gene platform (P or Q), please check the BG/P recipe in the installation documentation and note that the –enable-stat-at-open option is now recommended on those platforms.
Change log:
darshan-2.2.4

• Disable extra stat() of newly opened files by default. This improves performance on shared files for some platforms. Reported by Yushu Yao.
  • prevents Darshan from reporting SIZE_AT_OPEN, FILE_ALIGNENT, and DARSHAN_FILE_NOT_ALIGNED values
  • features can still be enabled via –enable-stat-at-open option
• Fix missing -lz in post ld flags reported by Yushu Yao. Fixes a link-time error for some corner-case applications.
• Fix bug in Cray compiler script patches that was setting compiler flags incorrectly. Reported by Yushu Yao.
  • WARNING: if you are using a previous Darshan release (2.2.3 through 2.2.4-pre4) on a Cray platform, please re-patch your compiler scripts.
• Update darshan-gen-* scripts to support the potential for additonal LDFLAGS or CFLAGS that appear before the object or source file in the compile or link commands. This fixes compatibility with some mvapich2 installations, reported by Dragos Constantin.

Darshan 2.2.3 is now available on the download page.  This release features official support for the Cray XE6 and IBM BG/Q platforms.  Special thanks to Yushu Yao and Katie Antypas of NERSC for their contributions in Cray integration and testing.
Change log:

Darshan 2.2.2 is now available on the download page.  Change log:

Darshan 2.2.0 is now available for download.   The biggest change is that this release splits the code into separate components for instrumentation and analysis.  There are also several improvements in documentation, portability, and an assortment of bug fixes.
Changelog: