From patchwork Mon Apr 29 13:16:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Puranjay Mohan X-Patchwork-Id: 13646947 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5961C7350E; Mon, 29 Apr 2024 13:17:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714396631; cv=none; b=bwKBNer82bUL/dynYscef8quC2HDNg1tnlquy2tnhs+sBrdb/L/tKQgLxl4VHiFGxbYZgVBgzJMPNjU6Ze5+aMPHz+3i//aA66q0ScWfKFsAZ3OidarV62c9dV+xnLujcqvXJ9gM+uYP8SaTf9xRz/TCeQ546MTp92uREnDmBhg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714396631; c=relaxed/simple; bh=w2Ysbdlw62K0XMPywgvp3DwJa4tgzeEkrintEchxF5U=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=DhSn6fQP53lhITcs863x0pSS8zvhhc4Zaf4N+fzwN7wlXuGQCU/hOQfXjKsWYVigSQyx3RXX/6VQ0SpxxHpICwtt/tuVZ5ZzNbyHHXnUgas14U6mYy2uhjsF7CqukmOnpcuqOAQFOxsTQ1fSjDgbGN90tV1MXnJtSqVGuRpssAw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jgZihBMK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jgZihBMK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAE3FC4AF19; Mon, 29 Apr 2024 13:17:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714396631; bh=w2Ysbdlw62K0XMPywgvp3DwJa4tgzeEkrintEchxF5U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jgZihBMKVPHRsloBrY/8lzLQ/TRynZHkNsHXz/ww9wRr+Av0CpfExPcWbDbhfkym5 GLSOpLPZ/BIInWmbkT6XLEK95VsCL5UwA7qIMCl4z38Nnntf60a4HXHilFRyV9+NWK LuTwupx/d/ttfDXaO3OrDC6l/o08n62KMxBajo6OO8Ffu+6xkZMwkVDGOEt5HrNhQI c+MZiKmjpb9m5d6flH8k4wT2v4QZlqPh+dBV0ywGnVAIJaRxaXUT73aRJxBcTELrmO j/lGMUQjBBkK+x0xzhxx6WZbQtx+PWNtFsbnSySP2vFAkaEs+sBKD0ASau85NA2c0A GbLpILZGFHTPg== From: Puranjay Mohan To: Catalin Marinas , Will Deacon , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Zi Shen Lim , Xu Kuohai , Florent Revest , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: puranjay12@gmail.com Subject: [PATCH bpf-next v4 2/2] bpf, arm64: inline bpf_get_smp_processor_id() helper Date: Mon, 29 Apr 2024 13:16:47 +0000 Message-Id: <20240429131647.50165-3-puranjay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240429131647.50165-1-puranjay@kernel.org> References: <20240429131647.50165-1-puranjay@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net As ARM64 JIT now implements BPF_MOV64_PERCPU_REG instruction, inline bpf_get_smp_processor_id(). ARM64 uses the per-cpu variable cpu_number to store the cpu id. Here is how the BPF and ARM64 JITed assembly changes after this commit: BPF ===== BEFORE AFTER -------- ------- int cpu = bpf_get_smp_processor_id(); int cpu = bpf_get_smp_processor_id(); (85) call bpf_get_smp_processor_id#229032 (18) r0 = 0xffff800082072008 (bf) r0 = &(void __percpu *)(r0) (61) r0 = *(u32 *)(r0 +0) ARM64 JIT =========== BEFORE AFTER -------- ------- int cpu = bpf_get_smp_processor_id(); int cpu = bpf_get_smp_processor_id(); mov x10, #0xfffffffffffff4d0 mov x7, #0xffff8000ffffffff movk x10, #0x802b, lsl #16 movk x7, #0x8207, lsl #16 movk x10, #0x8000, lsl #32 movk x7, #0x2008 blr x10 mrs x10, tpidr_el1 add x7, x0, #0x0 add x7, x7, x10 ldr w7, [x7] Performance improvement using benchmark[1] BEFORE AFTER -------- ------- glob-arr-inc : 23.817 ± 0.019M/s glob-arr-inc : 24.631 ± 0.027M/s [+ 3.41%] arr-inc : 23.253 ± 0.019M/s arr-inc : 23.742 ± 0.023M/s [+ 2.10%] hash-inc : 12.258 ± 0.010M/s hash-inc : 12.625 ± 0.004M/s [+ 3.00%] [1] https://github.com/anakryiko/linux/commit/8dec900975ef Signed-off-by: Puranjay Mohan Acked-by: Andrii Nakryiko --- kernel/bpf/verifier.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4e474ef44e9c..d0725b1c7bec 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -20273,19 +20273,33 @@ static int do_misc_fixups(struct bpf_verifier_env *env) goto next_insn; } -#ifdef CONFIG_X86_64 /* Implement bpf_get_smp_processor_id() inline. */ if (insn->imm == BPF_FUNC_get_smp_processor_id && prog->jit_requested && bpf_jit_supports_percpu_insn()) { /* BPF_FUNC_get_smp_processor_id inlining is an - * optimization, so if pcpu_hot.cpu_number is ever + * optimization, so if cpu_number_addr is ever * changed in some incompatible and hard to support * way, it's fine to back out this inlining logic */ - insn_buf[0] = BPF_MOV32_IMM(BPF_REG_0, (u32)(unsigned long)&pcpu_hot.cpu_number); - insn_buf[1] = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0); - insn_buf[2] = BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0); - cnt = 3; + u64 cpu_number_addr; + struct bpf_insn ld_insn[2] = { + BPF_LD_IMM64(BPF_REG_0, 0) + }; + +#if defined(CONFIG_X86_64) + cpu_number_addr = (u64)&pcpu_hot.cpu_number; +#elif defined(CONFIG_ARM64) + cpu_number_addr = (u64)&cpu_number; +#else + goto next_insn; +#endif + ld_insn[0].imm = (u32)cpu_number_addr; + ld_insn[1].imm = (u32)(cpu_number_addr >> 32); + insn_buf[0] = ld_insn[0]; + insn_buf[1] = ld_insn[1]; + insn_buf[2] = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0); + insn_buf[3] = BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0); + cnt = 4; new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) @@ -20296,7 +20310,6 @@ static int do_misc_fixups(struct bpf_verifier_env *env) insn = new_prog->insnsi + i + delta; goto next_insn; } -#endif /* Implement bpf_get_func_arg inline. */ if (prog_type == BPF_PROG_TYPE_TRACING && insn->imm == BPF_FUNC_get_func_arg) {