seccomp / libseccomp / 310

92%

main: 89%

Pull #204

travis-ci

syscalls, x86_64: use gperf

use gperf to generate a perfect hash to lookup syscall names.   It
improves significantly the complexity for seccomp_syscall_resolve_name.*
since it replaces the expensive strcmp for each syscall in the
database, with a lookup table.

The complexity for x86_64_syscall_resolve_num is not changed and it
uses the linear search, that is anyway less expensive than
seccomp_syscall_resolve_name.* as it uses an index for comparison
instead of doing a string comparison.

On my machine, calling 1000 seccomp_syscall_resolve_name_arch and
seccomp_syscall_resolve_num_arch over the entire syscalls DB passed
from ~0.45 sec to ~0.06s.

I've implemented it only for x86_64 as I've no access to other archs
for benchmarking the results.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

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