On Sonntag, 6. Dezember 2015 11:31:17 CET Paul Pluzhnikov wrote: > On Sun, Dec 6, 2015 at 11:03 AM, Arun Sharma <[email protected]> wrote: > > Suspect the comment below is relevant. Perhaps try removing it and see > > what happens? > > I suspect that the dlclose resulting in unload, followed by dlopen of > something else that lands in the same address range, is what would > break (by returning now stale info).
I've seen this bottleneck myself btw. in my heaptrack profiler - it costs both pure CPU performance as well as severely impacting the multi-thread performance. I was thinking of writing a patch for an off-by-default cache with the capability to manually invalidate the cache whenever dlopen/dlcose gets called (which is rare, and detectable by a profiler). I never got around to write it though... If anyone could do that - it would be much appreciated! That said, I did write this patch which is still not reviewed or accepted upstream: https://lists.gnu.org/archive/html/libunwind-devel/2015-09/msg00005.html @Luke: Could you try that patch and increase the cache size? That should already reduce the number of times dl_iterate_phdr gets called. @Arun: Any chance you could review and land it? Thanks -- Milian Wolff [email protected] http://milianw.de
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