From: David S. Miller Date: Fri, 17 Mar 2017 03:44:12 +0000 (-0700) Subject: Merge branch 'bpf-inline-lookups' X-Git-Tag: v4.12-rc1~64^3~419 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=3a70418b9c315ca4343d11a82bf1555043056d30;p=linux-block.git Merge branch 'bpf-inline-lookups' Alexei Starovoitov says: ==================== 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. ==================== Signed-off-by: David S. Miller --- 3a70418b9c315ca4343d11a82bf1555043056d30