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 [thread overview]
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 other threads:[~2019-07-24 16:58 UTC|newest]
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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