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https://github.com/opencontainers/runc.git
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Kir Kolyshkin
bbcf96f91f
Looking into data generated by setting
GODEBUG="inittrace=1"
I have noticed this line:
init github.com/opencontainers/runc/libcontainer/cgroups/devices @1.2 ms, 0.020 ms clock, 10512 bytes, 133 allocs
This is the leader for both bytes and allocs among the packages from
this repo, and all of it is caused by a single regex:
> var devicesListRegexp = regexp.MustCompile(`^([abc])\s+(\d+|\*):(\d+|\*)\s+([rwm]+)$`)
It seems that the same parsing can be done without relying on
a regular expression, no decrease in readability, and 2x faster
(according to the benchmark added), and also makes runc start
slightly faster and leaner.
Before:
BenchmarkParseLine-4 176240 6768 ns/op 6576 B/op 64 allocs/op
After:
BenchmarkParseLine-4 322441 3535 ns/op 5520 B/op 53 allocs/op
[v2: single split with SplitFunc; fix a typo in error message]
[v3: rebase after 3159 merge; re-ran benchmarks (results are similar)]
Co-authored-by: Sebastiaan van Stijn <github@gone.nl>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>