Em Tue, Mar 23, 2010 at 03:20:11PM +0100, Andi Kleen escreveu: > Soeren Sandmann <sandmann@xxxxxxxxxxx> writes: > > I don't think the oprofile JIT interface solves any of these > > problems. (In fact, I don't see why the JIT problem is even hard. The > > JIT compiler can just generate a little ELF file with symbols in it, > > and the profiler can pick it up through the mmap events that you get > > through the perf interface). > > That would require keeping those temporary ELF files for > potentially unlimited time around (profilers today look at the ELF > files at the final analysis phase, which might be weeks away) 'perf record' will traverse the perf.data file just collected and, if the binaries have build-ids, will stash them in ~/.debug/, keyed by build-id just like the -debuginfo packages do. So only the binaries with hits. Also one can use 'perf archive' to create a tar.bz2 file with the files with hits for the specified perf.data file, that can then be transfered to another machine, whatever arch, untarred at ~/.debug and then the report can be done there. As it is done by build-id, multiple 'perf record' sessions share files in the cache. Right now the whole ELF file (or /proc/kallsyms copy) is stored if collected from the DSO directly, or the bits that are stored in -debuginfo files if we find it installed (so smaller). We could strip that down further by storing just the ELF sections needed to make sense of the symtab. - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
