From patchwork Wed Apr 24 17:35:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Puranjay Mohan X-Patchwork-Id: 13642268 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 50AE416DECF; Wed, 24 Apr 2024 17:36:07 +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=1713980167; cv=none; b=J8HQbxGzxhRckaS90rOgC28IklvmX4Lrrsakb1914H+UjubVCR0Q/Kh8E4IB4jmC5iavk8KNsfA46oujenK2E18IWSAuNJuZ6gcuPoOmDT3wkTasZ5QrUX71wR+lrtL7GUs2dwYYGk6kpM6/MtiRrvnhhADYxtUXF/J2yW+wzWw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713980167; c=relaxed/simple; bh=FCXCpVbEo7vIvFYp4OCyiBsqhCLvLa3LgXOg2ugWL4w=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=WrqxlIjh1tuoOyB/aI07Qq97fkIsjai1hyrnVJagn+DxrwQF8LWFKu2OECSGK34gnAkyqgLdIyJY/vgJVIcuSlGXkYfhqIoscVRUsDBcbYIv8PQswggzPLyeWfTPLoGEMCssYRqLErPKbivuPKhvQ/fBYF6C9owA7TbvS7SY/Ss= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Zou6bT3k; 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="Zou6bT3k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F998C113CD; Wed, 24 Apr 2024 17:36:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713980166; bh=FCXCpVbEo7vIvFYp4OCyiBsqhCLvLa3LgXOg2ugWL4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zou6bT3kJB4Z59o91dJd1D91lUG/QZ7+1rEqTxMBWwUzlqSpekL1YLh+GGhwJWptJ WqXw9+Q0iL5y5p9drFYaButeIugf26dOKbjf7FDJmVaZ6Loo/o+W1lbRNT3GiJPdmX 0mssMvBx0qOXr5wWZfkkZRgFmHVNGTLZ1cqLin/X27mMQiF+cjWlUkdBbbZQ2Laai4 dPUDbcpMD/vQMLlJSBoJYgbfV0vK56M/0I1644jfjjOfIAoREe7FAxQkKS9SMEY3se rSw7fpOjZ3EwXp+41u+oTxiMGWEkJiUNKl29RraqUMwj9SIFANJoyRHKk2oHDgLfpR JILYj8rGSVqig== 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 v2 2/2] bpf, arm64: inline bpf_get_smp_processor_id() helper Date: Wed, 24 Apr 2024 17:35:50 +0000 Message-Id: <20240424173550.16359-3-puranjay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240424173550.16359-1-puranjay@kernel.org> References: <20240424173550.16359-1-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 = 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 arr-inc : 23.253 ± 0.019M/s arr-inc : 23.742 ± 0.023M/s hash-inc : 12.258 ± 0.010M/s hash-inc : 12.625 ± 0.004M/s [1] https://github.com/anakryiko/linux/commit/8dec900975ef Signed-off-by: Puranjay Mohan Acked-by: Andrii Nakryiko --- kernel/bpf/verifier.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9715c88cc025..3373be261889 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -20205,7 +20205,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env) goto next_insn; } -#ifdef CONFIG_X86_64 +#if defined(CONFIG_X86_64) || defined(CONFIG_ARM64) /* Implement bpf_get_smp_processor_id() inline. */ if (insn->imm == BPF_FUNC_get_smp_processor_id && prog->jit_requested && bpf_jit_supports_percpu_insn()) { @@ -20214,11 +20214,20 @@ static int do_misc_fixups(struct bpf_verifier_env *env) * changed in some incompatible and hard to support * way, it's fine to back out this inlining logic */ +#if defined(CONFIG_X86_64) 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; +#elif defined(CONFIG_ARM64) + struct bpf_insn cpu_number_addr[2] = { BPF_LD_IMM64(BPF_REG_0, (u64)&cpu_number) }; + insn_buf[0] = cpu_number_addr[0]; + insn_buf[1] = cpu_number_addr[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; +#endif new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) return -ENOMEM;