I did an experiment with one of our internal bpf programs. The program has 1563 insns.
Without Edward's patch: processed 13634 insns, stack depth 160 With Edward's patch: processed 15807 insns, stack depth 160 So the number of processed insns regressed by roughly 16%. Did anybody do any similar experiments to quantify the patch's impact in verification performance (e.g., in terms of processed insns)? On Tue, Jun 27, 2017 at 5:53 AM, Edward Cree via iovisor-dev <iovisor-...@lists.iovisor.org> wrote: > This series simplifies alignment tracking, generalises bounds tracking and > fixes some bounds-tracking bugs in the BPF verifier. Pointer arithmetic on > packet pointers, stack pointers, map value pointers and context pointers has > been unified, and bounds on these pointers are only checked when the pointer > is dereferenced. > Operations on pointers which destroy all relation to the original pointer > (such as multiplies and shifts) are disallowed if !env->allow_ptr_leaks, > otherwise they convert the pointer to an unknown scalar and feed it to the > normal scalar arithmetic handling. > Pointer types have been unified with the corresponding adjusted-pointer types > where those existed (e.g. PTR_TO_MAP_VALUE[_ADJ] or FRAME_PTR vs > PTR_TO_STACK); similarly, CONST_IMM and UNKNOWN_VALUE have been unified into > SCALAR_VALUE. > Pointer types (except CONST_PTR_TO_MAP, PTR_TO_MAP_VALUE_OR_NULL and > PTR_TO_PACKET_END, which do not allow arithmetic) have a 'fixed offset' and > a 'variable offset'; the former is used when e.g. adding an immediate or a > known-constant register, as long as it does not overflow. Otherwise the > latter is used, and any operation creating a new variable offset creates a > new 'id' (and, for PTR_TO_PACKET, clears the 'range'). > SCALAR_VALUEs use the 'variable offset' fields to track the range of possible > values; the 'fixed offset' should never be set on a scalar. > > As of patch 12/12, all tests of tools/testing/selftests/bpf/test_verifier > and tools/testing/selftests/bpf/test_align pass. > > v3: added a few more tests; removed RFC tags. > > v2: fixed nfp build, made test_align pass again and extended it with a few > new tests (though still need to add more). > > Edward Cree (12): > selftests/bpf: add test for mixed signed and unsigned bounds checks > bpf/verifier: rework value tracking > nfp: change bpf verifier hooks to match new verifier data structures > bpf/verifier: track signed and unsigned min/max values > bpf/verifier: more concise register state logs for constant var_off > selftests/bpf: change test_verifier expectations > selftests/bpf: rewrite test_align > selftests/bpf: add a test to test_align > selftests/bpf: add test for bogus operations on pointers > selftests/bpf: don't try to access past MAX_PACKET_OFF in > test_verifier > selftests/bpf: add tests for subtraction & negative numbers > selftests/bpf: variable offset negative tests > > drivers/net/ethernet/netronome/nfp/bpf/verifier.c | 24 +- > include/linux/bpf.h | 34 +- > include/linux/bpf_verifier.h | 56 +- > include/linux/tnum.h | 81 + > kernel/bpf/Makefile | 2 +- > kernel/bpf/tnum.c | 180 ++ > kernel/bpf/verifier.c | 1943 > ++++++++++++--------- > tools/testing/selftests/bpf/test_align.c | 462 ++++- > tools/testing/selftests/bpf/test_verifier.c | 293 ++-- > 9 files changed, 2034 insertions(+), 1041 deletions(-) > create mode 100644 include/linux/tnum.h > create mode 100644 kernel/bpf/tnum.c > > _______________________________________________ > iovisor-dev mailing list > iovisor-...@lists.iovisor.org > https://lists.iovisor.org/mailman/listinfo/iovisor-dev
