From: Brian Vazquez <brianvv@google.com> To: Brian Vazquez <brianvv.kernel@gmail.com>, Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, "David S . Miller" <davem@davemloft.net> Cc: Stanislav Fomichev <sdf@google.com>, Willem de Bruijn <willemb@google.com>, Petar Penkov <ppenkov@google.com>, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Brian Vazquez <brianvv@google.com> Subject: [PATCH bpf-next 0/6] bpf: add BPF_MAP_DUMP command to dump more than one entry per call Date: Wed, 24 Jul 2019 09:57:57 -0700 Message-ID: <20190724165803.87470-1-brianvv@google.com> (raw) This introduces a new command to retrieve multiple number of entries from a bpf map. This new command can be executed from the existing BPF syscall as follows: err = bpf(BPF_MAP_DUMP, union bpf_attr *attr, u32 size) using attr->dump.map_fd, attr->dump.prev_key, attr->dump.buf, attr->dump.buf_len returns zero or negative error, and populates buf and buf_len on succees This implementation is wrapping the existing bpf methods: map_get_next_key and map_lookup_elem Note that this implementation can be extended later to do dump and delete by extending map_lookup_and_delete_elem (currently it only works for bpf queue/stack maps) and either use a new flag in map_dump or a new command map_dump_and_delete. Results show that even with a 1-elem_size buffer, it runs ~40 faster than the current implementation, improvements of ~85% are reported when the buffer size is increased, although, after the buffer size is around 5% of the total number of entries there's no huge difference in increasing it. Tested: Tried different size buffers to handle case where the bulk is bigger, or the elements to retrieve are less than the existing ones, all runs read a map of 100K entries. Below are the results(in ns) from the different runs: buf_len_1: 69038725 entry-by-entry: 112384424 improvement 38.569134 buf_len_2: 40897447 entry-by-entry: 111030546 improvement 63.165590 buf_len_230: 13652714 entry-by-entry: 111694058 improvement 87.776687 buf_len_5000: 13576271 entry-by-entry: 111101169 improvement 87.780263 buf_len_73000: 14694343 entry-by-entry: 111740162 improvement 86.849542 buf_len_100000: 13745969 entry-by-entry: 114151991 improvement 87.958187 buf_len_234567: 14329834 entry-by-entry: 114427589 improvement 87.476941 The series of patches are split as follows: - First patch move some map_lookup_elem logic into 2 fucntions to deduplicate code: bpf_map_value_size and bpf_map_copy_value - Second patch introduce map_dump function - Third patch syncs tools linux headers - Fourth patch adds libbpf support - Last two patches adds tests RFC Changelog: - remove wrong usage of attr.flags - move map_fd to remove hole after it v3: - add explanation of the API in the commit message - fix masked errors and return them to user - copy last_key from return buf into prev_key if it was provided - run perf test with kpti and retpoline mitigations v2: - use proper bpf-next tag Brian Vazquez (6): bpf: add bpf_map_value_size and bp_map_copy_value helper functions bpf: add BPF_MAP_DUMP command to dump more than one entry per call bpf: keep bpf.h in sync with tools/ libbpf: support BPF_MAP_DUMP command selftests/bpf: test BPF_MAP_DUMP command on a bpf hashmap selftests/bpf: add test to measure performance of BPF_MAP_DUMP include/uapi/linux/bpf.h | 9 + kernel/bpf/syscall.c | 251 ++++++++++++++++++------ tools/include/uapi/linux/bpf.h | 9 + tools/lib/bpf/bpf.c | 28 +++ tools/lib/bpf/bpf.h | 4 + tools/lib/bpf/libbpf.map | 2 + tools/testing/selftests/bpf/test_maps.c | 148 +++++++++++++- 7 files changed, 388 insertions(+), 63 deletions(-) -- 2.22.0.657.g960e92d24f-goog
next reply index Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-07-24 16:57 Brian Vazquez [this message] 2019-07-24 16:57 ` [PATCH bpf-next 1/6] bpf: add bpf_map_value_size and bp_map_copy_value helper functions Brian Vazquez 2019-07-24 20:53 ` Song Liu 2019-07-24 16:57 ` [PATCH bpf-next 2/6] bpf: add BPF_MAP_DUMP command to dump more than one entry per call Brian Vazquez 2019-07-24 19:54 ` Willem de Bruijn 2019-07-24 22:26 ` Brian Vazquez 2019-07-24 22:33 ` Willem de Bruijn 2019-07-24 21:40 ` Song Liu 2019-07-24 22:44 ` Brian Vazquez 2019-07-24 23:04 ` Song Liu 2019-07-25 23:25 ` Brian Vazquez 2019-07-25 23:54 ` Alexei Starovoitov 2019-07-26 1:02 ` Willem de Bruijn 2019-07-26 1:24 ` Brian Vazquez 2019-07-26 1:47 ` Alexei Starovoitov 2019-07-26 6:10 ` Yonghong Song 2019-07-26 23:36 ` Brian Vazquez 2019-07-27 0:02 ` Jakub Kicinski 2019-07-27 17:54 ` Yonghong Song 2019-07-24 16:58 ` [PATCH bpf-next 3/6] bpf: keep bpf.h in sync with tools/ Brian Vazquez 2019-07-24 21:41 ` Song Liu 2019-07-24 23:10 ` Andrii Nakryiko 2019-07-25 23:27 ` Brian Vazquez 2019-07-24 16:58 ` [PATCH bpf-next 4/6] libbpf: support BPF_MAP_DUMP command Brian Vazquez 2019-07-24 19:51 ` Willem de Bruijn 2019-07-24 16:58 ` [PATCH bpf-next 5/6] selftests/bpf: test BPF_MAP_DUMP command on a bpf hashmap Brian Vazquez 2019-07-24 21:58 ` Song Liu 2019-07-24 16:58 ` [PATCH bpf-next 6/6] selftests/bpf: add test to measure performance of BPF_MAP_DUMP Brian Vazquez 2019-07-24 22:01 ` Song Liu 2019-07-24 19:20 ` [PATCH bpf-next 0/6] bpf: add BPF_MAP_DUMP command to dump more than one entry per call Song Liu 2019-07-24 22:15 ` Brian Vazquez
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