btf: optimize stringTable to speed up vmlinux parsing #1203
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The library now uses stringTableBuilder instead. Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
It turns out that the vast majority of string table lookups are for
offset zero, which is always defined to be the empty string.
This gives a good 14% speedup on my machine:
goos: linux
goarch: amd64
pkg: github.com/cilium/ebpf/btf
cpu: 12th Gen Intel(R) Core(TM) i7-1260P
│ base.txt │ zero.txt │
│ sec/op │ sec/op vs base │
ParseVmlinux-16 50.14m ± 7% 43.07m ± 3% -14.10% (p=0.002 n=6)
│ base.txt │ zero.txt │
│ B/op │ B/op vs base │
ParseVmlinux-16 31.45Mi ± 0% 31.45Mi ± 0% ~ (p=0.485 n=6)
│ base.txt │ zero.txt │
│ allocs/op │ allocs/op vs base │
ParseVmlinux-16 534.1k ± 0% 534.1k ± 0% ~ (p=0.461 n=6)
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
dylandreimerink
approved these changes
Nov 4, 2023
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btf: remove unused stringTable.Marshal
btf: add fast path for string table offset 0 lookup