On Mon, 18 Nov 2013 18:49:45 +0100, Jiri Olsa wrote: > I think it's an option.. but it'll simpler to try the libdw > interface first and see if it's good/fast enough..
The elfutils libdw unwinder is being upstreamed these weeks, the x86* unwinder itself is already upstream now. > also I recall discussing the speed with libdw developer My tests with perf using elfutils unwinder were 10x faster than libunwind; this is by some simple caching of ELF files. Sure a similar cache could be implemented also for libunwind. But the cache is a wrong solution. The problem is that currently perf loads the ELF files again and again for every process as the ELF file always gets automatically relocated for the address where it was loaded. The right way is to load the ELF file only once and access always the same copy with process-specific displacement only. I did not investigate how much feasible it is with libunwind. For elfutils there is pmachata/sharing unfinished branch from 2008 to implement that. I have not checked it more before the unwinder gets fully upstreamed. Jan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
