tree 5628b02bc8ae2407af46880b3070ba61fdb4c8b6
parent cf20a499655583a985eb959f98fae9c2e7ecf189
author Andrii Nakryiko <andriin@fb.com> 1583434972 -0800
committer yonghong-song <ys114321@gmail.com> 1583646738 -0800

libbpf-tools: optimize ksyms cache

Re-implement internals of ksyms cache to minimize memory overhead and
allocations. Addr is also changed to be unsigned long.

fscanf() can be further optimized into manual parsing, but it's low enough
overhead right now that I felt like readibility is more important.

Benchmarking ksyms loading/parsing parts:

BEFORE:
$ /usr/bin/time ./test
0.03user 0.04system 0:00.08elapsed 98%CPU (0avgtext+0avgdata 6968maxresident)k
0inputs+0outputs (0major+1512minor)pagefaults 0swaps

AFTER:
$ /usr/bin/time ./test
0.02user 0.03system 0:00.06elapsed 100%CPU (0avgtext+0avgdata 9508maxresident)k
  0inputs+0outputs (0major+2106minor)pagefaults 0swaps

RSS goes down from 9.5MB to <7MB, while CPU time went up about 20ms.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>