Allow use of llvm-addr2line as the command #18
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Prior to this change the addr2line.py script always uses addr2line as the binary to decode stack frames. This change allows the path and/or name of the binary to be provided explicitly on the command line. This allows the of llvm-addr2line, an alternative implementation based on llvm-symbolizer, which in my experiments is over *200* times as fast as addr2line in decoding some redpanda stack traces. See https://sourceware.org/bugzilla/show_bug.cgi?id=29010 for more on the addr2line slowness. This change also slightly changes the 'dummy line' strategy used to detect when addr2line has finished outputting frames for the current address to make it compatible with llvm-addr2line. Fixes scylladb#1035.
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| r"(.*0x0000000000000000: \?\? \?\?:0\n)" # addr2line pattern | ||
| r"|" | ||
| r"(.*0x0: \?\? at \?\?:0\n)" # llvm-addr2line pattern | ||
| ) |
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The main complication is the slightly differnet "end of backtrace" beahvior for llvm-addr2line: the 0x0 frame we use to find it looks a bit different. Use a regex to accommodate the differences.
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Hello Seastar cousins, thanks for discovering the issue and feel free to post a pull request upstream as well :) Pull requests are also accepted in scylladb/seastar, so no need for a separate mailing list patch. |
:) That's wonderful news @psarna |
Yes! I'll do that next. |
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@jcsp everything look good here to you? |
Prior to this change the addr2line.py script always uses addr2line as the
binary to decode stack frames. This change allows the path and/or name
of the binary to be provided explicitly on the command line.
This allows the of llvm-addr2line, an alternative implementation
based on llvm-symbolizer, which in my experiments is over 200 times as
fast as addr2line in decoding some redpanda stack traces.
See https://sourceware.org/bugzilla/show_bug.cgi?id=29010 for more
on the addr2line slowness.
This change also slightly changes the 'dummy line' strategy used to
detect when addr2line has finished outputting frames for the current
address to make it compatible with llvm-addr2line.
Fixes scylladb#1035.