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[Bug translator/14820] hang when running semok/nodwf01.stp
- From: "dsmith at redhat dot com" <sourceware-bugzilla at sourceware dot org>
- To: systemtap at sourceware dot org
- Date: Mon, 12 Nov 2012 17:03:34 +0000
- Subject: [Bug translator/14820] hang when running semok/nodwf01.stp
- Auto-submitted: auto-generated
- References: <bug-14820-6586@http.sourceware.org/bugzilla/>
http://sourceware.org/bugzilla/show_bug.cgi?id=14820
--- Comment #1 from David Smith <dsmith at redhat dot com> 2012-11-12 17:03:34 UTC ---
Here's an update on this one. This also happens on a 1M vm (running
2.6.32-279.14.1.el6.x86_64).
With some debug prints added, I now believe that module_info::update_symtab()
really isn't the problem, that either elfutils or dwflpp.cxx is. Basically the
problem is that we're finding *way* too many function aliases when we don't
have dwarf info.
Here's a couple of randomly chosen functions:
piix4_io_quirk: 0 aliases with dwarf info, ~660 aliases without dwarf info
native_read_cr4_safe: 0 aliases with dwarf info, ~1320 aliases without dwarf
info
Without dwarf info, I'm seeing innermost loop of module_info::update_symtab()
find almost 18 million aliases (if I'm reading my debug output correctly). I
believe the hang here is just the time being taken trying to insert that many
items into the hash table.
I'd guess the problem is in map_by_addr.equal_range(), but I could certainly be
wrong.
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