https://docs-archive.hpc.udel.edu/ Tue, 14 Apr 2026 22:00:56 +0000 FeedCreator 1.8 https://docs-archive.hpc.udel.edu/_media/wiki/dokuwiki.svg https://docs-archive.hpc.udel.edu/ https://docs-archive.hpc.udel.edu/technical/whitepaper/automated_devshm_cleanup Automated /dev/shm cleanup Historically, shared memory was an IPC facility whereby one process could mark memory segments as being shared, and other processes on the same machine could map those segments into their memory space. Segments had a key that identified them, and the key had to be shared to dependent processes that wanted to map the segment. This was often accomplished by: anonymous@undisclosed.example.com (Anonymous) Thu, 13 Dec 2018 18:02:26 +0000 https://docs-archive.hpc.udel.edu/technical/whitepaper/darwin_ucx_openmpi Mellanox UCX and Open MPI on DARWIN During early-access testing of the DARWIN cluster, several users reported unexpected crashes of their Open MPI applications. The crashes were accompanied by a running stream of kernel messages: : [Sat Feb 6 16:51:55 2021] infiniband mlx5_0: create_mkey_callback:148:(pid 0): async reg mr failed. status -12 [Sat Feb 6 16:51:55 2021] mlx5_core 0000:81:00.0: mlx5_cmd_check:794:(pid 0): CREATE_MKEY(0x200) op_mod(0x0) failed, status limits exceeded(0x8), syn… anonymous@undisclosed.example.com (Anonymous) Fri, 12 Feb 2021 22:15:41 +0000 https://docs-archive.hpc.udel.edu/technical/whitepaper/hpcc-open64-acml HPCC with open64 compiler, ACML and base FFT Make Here are som modifications on Mills based on recommendations from Using ACML (AMD Core Math Library) In High Performance Computing Challenge (HPCC) Changes to the make file hpl/setup/Make.Linux_ATHLON_FBLAS copied to hpl/Make.open64-acml * Comment lines beginning in MP or LA anonymous@undisclosed.example.com (Anonymous) Tue, 27 Apr 2021 20:21:09 +0000 https://docs-archive.hpc.udel.edu/technical/whitepaper/openmpi-psm2-spawn Open MPI, PSM2, and MPI_Comm_spawn() MPI programs have always started with the worker processes described as the world for the computation (MPI_COMM_WORLD). The MPI-2 standard includes the concept of something larger than that world: the universe encompasses all processing resources available, where the anonymous@undisclosed.example.com (Anonymous) Tue, 29 Mar 2022 15:45:19 +0000 https://docs-archive.hpc.udel.edu/technical/whitepaper/r-runtime-blas-lapack R: Runtime-configuration BLAS/LAPACK The R Project for Statistical Computing is used on our clusters by a wide variety of scientific disciplines. Though the breadth of applications is wide, many of them require the functionality of BLAS/LAPACK libraries. R provides its own baseline implementations that will build on any system; naturally, one cannot expect these anonymous@undisclosed.example.com (Anonymous) Mon, 10 Dec 2018 17:40:38 +0000 https://docs-archive.hpc.udel.edu/technical/whitepaper/rjava-gcc-optimization rJava: when compilers get too smart In the midst of installing the thousands of packages available in the CRAN library, a subset of the packages displayed a curious behavior: when R attempted to load the package to verify installation, the R subprocess would hang indefinitely. With timeouts in place, the installation of the package eventually fails. anonymous@undisclosed.example.com (Anonymous) Fri, 17 Jun 2022 18:58:18 +0000 https://docs-archive.hpc.udel.edu/technical/whitepaper/start White Papers Some of the content in this area will be in PDF format and may need to be downloaded before being read. rJava: When Compilers Get Too Smart While installing all 16k (nearly 17k) CRAN packages on a recent R 4.1.3 build, many packages with a dependency on rJava would hang when being tested. anonymous@undisclosed.example.com (Anonymous) Fri, 17 Jun 2022 16:25:18 +0000