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Date: Wed, 15 Mar 2017 18:26:38 -0700 From: Alexei Starovoitov <ast@...com> To: "David S . Miller" <davem@...emloft.net> CC: Daniel Borkmann <daniel@...earbox.net>, Fengguang Wu <fengguang.wu@...el.com>, <netdev@...r.kernel.org>, <kernel-team@...com> Subject: [PATCH net-next 0/6] bpf: inline bpf_map_lookup_elem() bpf_map_lookup_elem() is one of the most frequently used helper functions. Improve JITed program performance by inlining this helper. bpf_map_type before after hash 58M 74M array 174M 280M The values are number of lookups per second in ideal conditions measured by micro-benchmark in patch 6. The 'perf report' for HASH map type: before: 54.23% map_perf_test [kernel.kallsyms] [k] __htab_map_lookup_elem 14.24% map_perf_test [kernel.kallsyms] [k] lookup_elem_raw 8.84% map_perf_test [kernel.kallsyms] [k] htab_map_lookup_elem 5.93% map_perf_test [kernel.kallsyms] [k] bpf_map_lookup_elem 2.30% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2 1.49% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler after: 60.03% map_perf_test [kernel.kallsyms] [k] __htab_map_lookup_elem 18.07% map_perf_test [kernel.kallsyms] [k] lookup_elem_raw 2.91% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2 1.94% map_perf_test [kernel.kallsyms] [k] _einittext 1.90% map_perf_test [kernel.kallsyms] [k] __audit_syscall_exit 1.72% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler so the cost of htab_map_lookup_elem() and bpf_map_lookup_elem() is gone after inlining. 'per-cpu' and 'lru' map types can be optimized similarly in the future. Note the sparse will complain that bpf is addictive ;) kernel/bpf/hashtab.c:438:19: sparse: subtraction of functions? Share your drugs kernel/bpf/verifier.c:3342:38: sparse: subtraction of functions? Share your drugs it's not a new warning, just in new places. Alexei Starovoitov (6): bpf: move fixup_bpf_calls() function bpf: refactor fixup_bpf_calls() bpf: adjust insn_aux_data when patching insns bpf: add helper inlining infra and optimize map_array lookup bpf: inline htab_map_lookup_elem() samples/bpf: add map_lookup microbenchmark include/linux/bpf.h | 1 + include/linux/bpf_verifier.h | 5 +- include/linux/filter.h | 10 +++ kernel/bpf/arraymap.c | 29 +++++++++ kernel/bpf/hashtab.c | 31 +++++++++- kernel/bpf/syscall.c | 56 ----------------- kernel/bpf/verifier.c | 129 ++++++++++++++++++++++++++++++++++++--- samples/bpf/map_perf_test_kern.c | 33 ++++++++++ samples/bpf/map_perf_test_user.c | 32 ++++++++++ 9 files changed, 261 insertions(+), 65 deletions(-) -- 2.8.0
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