broker: reduce the number of mallocs in logging path #6917
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Problem: Each log buffer entry requires two mallocs to allocate. Allocate the ring buffer entry struct and buffer member with one malloc call.
grondo
approved these changes
Jul 17, 2025
Problem: the use of zlist_t in the logging ring buffer implementation means that a list node has to be separately allocated each time a log entry is appended to the ring. Switch to a CCAN list which embeds the list node in the log entry struct and thus avoid the extra malloc call.
Huh! I didn't expect that! Sorry for the force pushes: one sloppy error, one pedantic compiler warning we always hit with list_for_each. |
Well I should have added a ;-) |
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OK, setting MWP! |
Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## master #6917 +/- ##
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Coverage 83.90% 83.90%
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Files 540 540
Lines 90539 90525 -14
=======================================
- Hits 75963 75957 -6
+ Misses 14576 14568 -8
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Problem: the broker ring buffer implementation is malloc-heavy.
This converts the logging ring buffer from
zlist_tto a CCAN list so that a list node doesn't need to be allocated each time an entry is appended to the ring. It also combines two mallocs used to allocate a list entry into one.This is probably not significant since our log volume is not too crazy, but it was an easy change, so there.