diff options
| author | Giuseppe Scrivano <gscrivan@redhat.com> | 2020-01-23 17:01:39 +0100 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2020-03-23 11:14:35 -0400 |
| commit | 9b129c41ac1f43d373742697aa2faf6040b9dfab (patch) | |
| tree | 25c69d113e954473adb7b5209c76b67773a383e9 /configure.ac | |
| parent | f5b3166d6126f4a45b59d6af6780b5e00a0e9867 (diff) | |
| download | libseccomp-9b129c41ac1f43d373742697aa2faf6040b9dfab.tar.gz | |
arch: use gperf to generate a perfact hash to lookup syscall names
This patch significantly improves the performance of
seccomp_syscall_resolve_name since it replaces the expensive strcmp
for each syscall in the database, with a lookup table.
The complexity for 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.
PM: After talking with Giuseppe I made a number of additional
changes, some substantial, the highlights include:
* various style tweaks
* .gitignore fixes
* fixed subject line, tweaked the description
* dropped the arch-syscall-validate changes as they were masking
other problems
* extracted the syscalls.csv and file deletions to other patches
to keep this one more focused
* fixed the x86, x32, arm, all the MIPS ABIs, s390, and s390x ABIs as
the syscall offsets were not properly incorporated into this change
* cleaned up the ABI specific headers
* cleaned up generate_syscalls_perf.sh and renamed to
arch-gperf-generate
* fixed problems with automake's file packaging
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Tom Hromatka <tom.hromatka@oracle.com>
[PM: see notes in the "PM" section above]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index e8b77f2..40d9dcb 100644 --- a/configure.ac +++ b/configure.ac @@ -119,6 +119,11 @@ AC_DEFINE_UNQUOTED([ENABLE_PYTHON], [$(test "$enable_python" = yes && echo 1 || echo 0)], [Python bindings build flag.]) +AC_CHECK_TOOL(GPERF, gperf) +if test -z "$GPERF"; then + AC_MSG_ERROR([please install gperf]) +fi + dnl #### dnl coverity checks dnl #### |