slightly reduce the range of hashed name lengths #629
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v0.8.0 was improved to obfuscate names so that they didn't all end up with the same length. We went from a length fixed to 8 to a range between 8 and 15. Since the new mechanism chooses a length evenly between 8 and 15, the average hashed name length went from 8 to 11.5. While this improved obfuscation, it also increased the size of obfuscated binaries by quite a bit. We do need to use a reasonably large length to avoid collisions within packages, but we also don't want it to be large enough to cause too much bloat. Reduce the minimum and maximum from 8 and 15 to 6 and 12. This means that the average goes fro 11.5 to 9, much closer to the old average. We could consider a range of 4 to 12, but 4 bytes is short enough where collisions become likely in practice, even if it's just the minimum. And a range of 6 to 10 shrinks the range a bit too much. name old time/op new time/op delta Build-16 20.6s ± 0% 20.6s ± 0% ~ (p=0.421 n=5+5) name old bin-B new bin-B delta Build-16 5.77M ± 0% 5.66M ± 0% -1.92% (p=0.008 n=5+5) name old cached-time/op new cached-time/op delta Build-16 705ms ± 4% 703ms ± 2% ~ (p=0.690 n=5+5) name old mallocs/op new mallocs/op delta Build-16 25.0M ± 0% 25.0M ± 0% -0.08% (p=0.008 n=5+5) name old sys-time/op new sys-time/op delta Build-16 8.11s ± 2% 8.11s ± 2% ~ (p=0.841 n=5+5) Updates burrowers#618.
lu4p
approved these changes
Jan 7, 2023
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(see commit message)
Updates #618.