From: Chris Chaudoir (csc4561_at_cacs.louisiana.edu)
Date: Fri Nov 13 2009 - 10:56:23 PST
Paul, Thanks for the info...any advice on where is the best place to jump into the source code? Thanks, -Chris On Tue, Nov 10, 2009 at 4:02 PM, Paul H. Hargrove <PHHargrove_at_lbl_dot_gov>wrote: > Chris, > > Currently BLCR will exclude : > 1) Pages mapped from a file and unmodified, which will include the code and > read-only data segments of the executable and shared libraries. This may > also included mmap()s performed by the application, if any. > 2) "Anonymous" (non file-backed) pages that are mapped in to the process > but not yet written to, which includes unused portions of the stack and > heap. > > In the next release (target Jan 2010) we will have a mechanism that allows > applications and libraries to hint to BLCR about regions of memory that can > be excluded. For instance, the OpenMPI developer that works on > checkpoint/restart has suggested that they might exclude any of MPI's > receive buffers that don't hold actual messages at the time the checkpoint > is taken. > > We are also working on incremental checkpointing for the next release. In > the case where one takes multiple checkpoints of the same process over time, > this will omit from a checkpoint any pages not written to since the previous > one. However, when using this mechanism one needs all the past checkpoints > to restore (and so more disk space is required). > > -Paul > > > Chris Chaudoir wrote: > >> To Paul et all, >> I just started playing around with the latest version of BLCR (nice btw) >> and had a question...besides the expected methods of skipping the code and >> unused stack, can you describe the 'memory exclusion' methods in BLCR (or >> point me to the right documentation)? >> Respectfully, >> Chris Chaudoir >> BSEE & CS grad student >> >> > > > -- > Paul H. Hargrove PHHargrove_at_lbl_dot_gov > Future Technologies Group Tel: +1-510-495-2352 > HPC Research Department Fax: +1-510-486-6900 > Lawrence Berkeley National Laboratory >