From 2ddec2c80b4402c293c7e6e0881cecaaf77e8cec Mon Sep 17 00:00:00 2001 From: Puranjay Mohan Date: Thu, 2 May 2024 15:18:52 +0000 Subject: riscv, bpf: inline bpf_get_smp_processor_id() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Inline the calls to bpf_get_smp_processor_id() in the riscv bpf jit. RISCV saves the pointer to the CPU's task_struct in the TP (thread pointer) register. This makes it trivial to get the CPU's processor id. As thread_info is the first member of task_struct, we can read the processor id from TP + offsetof(struct thread_info, cpu). RISCV64 JIT output for `call bpf_get_smp_processor_id` ====================================================== Before After -------- ------- auipc t1,0x848c ld a5,32(tp) jalr 604(t1) mv a5,a0 Benchmark using [1] on Qemu. ./benchs/run_bench_trigger.sh glob-arr-inc arr-inc hash-inc +---------------+------------------+------------------+--------------+ | Name | Before | After | % change | |---------------+------------------+------------------+--------------| | glob-arr-inc | 1.077 ± 0.006M/s | 1.336 ± 0.010M/s | + 24.04% | | arr-inc | 1.078 ± 0.002M/s | 1.332 ± 0.015M/s | + 23.56% | | hash-inc | 0.494 ± 0.004M/s | 0.653 ± 0.001M/s | + 32.18% | +---------------+------------------+------------------+--------------+ NOTE: This benchmark includes changes from this patch and the previous patch that implemented the per-cpu insn. [1] https://github.com/anakryiko/linux/commit/8dec900975ef Signed-off-by: Puranjay Mohan Acked-by: Kumar Kartikeya Dwivedi Acked-by: Andrii Nakryiko Acked-by: Björn Töpel Link: https://lore.kernel.org/r/20240502151854.9810-3-puranjay@kernel.org Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index 7a27f19bf44d..3e19bb62ed1a 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -993,6 +993,7 @@ u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog); void bpf_jit_compile(struct bpf_prog *prog); bool bpf_jit_needs_zext(void); +bool bpf_jit_inlines_helper_call(s32 imm); bool bpf_jit_supports_subprog_tailcalls(void); bool bpf_jit_supports_percpu_insn(void); bool bpf_jit_supports_kfunc_call(void); -- cgit v1.2.3