Inline the calls to bpf_get_smp_processor_id() in the powerpc bpf jit. powerpc saves the Logical processor number (paca_index) in paca.
Here is how the powerpc JITed assembly changes after this commit: Before: cpu = bpf_get_smp_processor_id(); addis 12, 2, -517 addi 12, 12, -29456 mtctr 12 bctrl mr 8, 3 After: cpu = bpf_get_smp_processor_id(); lhz 8, 8(13) To evaluate the performance improvements introduced by this change, the benchmark described in [1] was employed. +---------------+-------------------+-------------------+--------------+ | Name | Before | After | % change | |---------------+-------------------+-------------------+--------------| | glob-arr-inc | 41.580 ± 0.034M/s | 54.137 ± 0.019M/s | + 30.20% | | arr-inc | 39.592 ± 0.055M/s | 54.000 ± 0.026M/s | + 36.39% | | hash-inc | 25.873 ± 0.012M/s | 26.334 ± 0.058M/s | + 1.78% | +---------------+-------------------+-------------------+--------------+ [1] https://github.com/anakryiko/linux/commit/8dec900975ef Signed-off-by: Saket Kumar Bhaskar <sk...@linux.ibm.com> --- arch/powerpc/net/bpf_jit_comp.c | 10 ++++++++++ arch/powerpc/net/bpf_jit_comp64.c | 5 +++++ 2 files changed, 15 insertions(+) diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 3d4bd45a9a22..4b79b2d95469 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -445,6 +445,16 @@ bool bpf_jit_supports_percpu_insn(void) return true; } +bool bpf_jit_inlines_helper_call(s32 imm) +{ + switch (imm) { + case BPF_FUNC_get_smp_processor_id: + return true; + default: + return false; + } +} + void *arch_alloc_bpf_trampoline(unsigned int size) { return bpf_prog_pack_alloc(size, bpf_jit_fill_ill_insns); diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 06f06770ceea..a8de12c026da 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -1087,6 +1087,11 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct code case BPF_JMP | BPF_CALL: ctx->seen |= SEEN_FUNC; + if (insn[i].src_reg == 0 && imm == BPF_FUNC_get_smp_processor_id) { + EMIT(PPC_RAW_LHZ(bpf_to_ppc(BPF_REG_0), _R13, offsetof(struct paca_struct, paca_index))); + break; + } + ret = bpf_jit_get_func_addr(fp, &insn[i], extra_pass, &func_addr, &func_addr_fixed); if (ret < 0) -- 2.43.5
