If you can share before/after output from -log_view, it would likely help localize.
Another unintrusive thing (if you're allowed to run Linux perf) is to $ perf record --call-graph dwarf -F99 ./app [... runs ...] $ perf script | stackcollapse-perf | flamegraph > flame.svg and open flame.svg in a browser (it's interactive). This uses the flamegraph tools (https://github.com/brendangregg/FlameGraph). You can direct `perf script` to a file and share that if you can't/won't install flamegraph. This doesn't require compiling any special way and yet helps understand where time is spent. Adrian Croucher <a.crouc...@auckland.ac.nz> writes: > hi, > > We have our PETSc-based code compiled on a Cray XC-50 machine, and it > has just recently started running about 2.5 times slower on there. > Neither the code nor PETSc has been recompiled lately. > > Turning the PETSc logging on, it appears to be spending more time on I/O > than it used to. > > The cluster admins have suggested we rebuild with the Cray "perftools" > module loaded to get profiling info. It's a slight hassle to rebuild > everything, so I wondered, would this actually tell us anything that we > don't already know from the PETSc logs? > > - Adrian > > -- > Dr Adrian Croucher > Senior Research Fellow > Department of Engineering Science > University of Auckland, New Zealand > email: a.crouc...@auckland.ac.nz > tel: +64 (0)9 923 4611
