Improve ELF symbolization performance#1546
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d-e-s-o merged 2 commits intolibbpf:mainfrom Apr 17, 2026
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Switch create_by_addr_idx() from sort_by() to sort_unstable_by(). The stable sort allocates a temporary buffer equal in size to the input for its merge phase. The unstable variant sorts in-place instead. Stability is not required here because the secondary sort key (size descending) already fully determines the order among equal-address symbols. Apply the same change to create_str2sym()'s sort_by_key() call. Signed-off-by: Daniel Müller <deso@posteo.net>
Pre-allocate the by_addr_idx vector in create_by_addr_idx() using the total symbol count as a capacity hint. The previous code collected filtered indices into a Box<[usize]> via the iterator's collect(), which has no size hint from the filter adapter and repeatedly reallocates as the vector grows. Since the majority of symbols pass the matches() filter, syms.len() is a close upper bound that minimizes intermediate reallocations. Taken together with the previous change we see a sizable improvement for the symbolize_elf benchmark: > main/symbolize_elf > time: [5.5718 ms 5.6047 ms 5.6519 ms] > change: [−35.225% −34.714% −34.109%] (p = 0.00 < 0.02) > Performance has improved. Signed-off-by: Daniel Müller <deso@posteo.net>
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #1546 +/- ##
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- Coverage 95.50% 95.37% -0.13%
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Files 56 56
Lines 9534 9534
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- Hits 9105 9093 -12
- Misses 429 441 +12 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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