From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (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 5A021C148 for ; Sat, 23 Nov 2024 01:00:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732323617; cv=none; b=QtBOZXzNKENVaKipV6xmqKL5urfBXJCNWCSdhGFnFHeyVNn5aKjWckHuHs7B452TSEffumdc2RoQXJUbPW6JyWZeJZDfcABCE3ahfsbwMNd35s7RxuiiEx3IH+9Gethrk/ufKwwLh0uh5e9y+vQbsizUYFZ6AaAd9E4JLnJqUC4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732323617; c=relaxed/simple; bh=7cs3jHCiUEKc3N5DyHJKSnimVAbV/s5jG4L1c08fPwI=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Pko3cQHDehBgmBw3IQgaIcj7K+4FiEyrtoTNqL5/oBAP9mKVP81Pl2LatEgEGZnFOLsZf2MKjqOcCNxzVIqQ1kksl6qg9BEkim2GYIKcPsa4KRPKmVVzMk19Ads+A+QScOvrNAs+b+4vtmvRlhbi07DchsSsaw99WYi2CtdJawo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=S812OZi0; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b="S812OZi0" Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4AMLTlnK011576; Fri, 22 Nov 2024 16:59:31 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=s2048-2021-q4; bh=AXJpK+akigy2/hzFSxdub52G/nO+rxhmJT8Lh98jAf0=; b=S812OZi0h9wq oOLVOCP1gZaKf6G2q9KC3HjkIma+SBALxRUwt7bqBeLGcvlmoBCTR47o3jNZhs/g Q1+44qt6ChMbkC9glBcoCARULiKWioB4hO0k6/cWYAa2laCApjhRnde6+nLBld17 Sa+kOuL9gVDmhd5Jd80BF7kiiL6vfk+DLEyznCaqk5/FsEQMsNkNMSru0Cf87tjr ct0hmcdH7CYb94Z9FdYsa6AYkQz4+0rMpiuoS3ORRf7KAeYhqIfNxMGdhiilkF8m KQg9gEb7aM/eJyDnKas4viF046Cx9GsjXOF0G41crpDiHvWn4ZKLytza+LKrK2rA ThuwuQ7npA== Received: from maileast.thefacebook.com ([163.114.135.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 4331wrh333-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Fri, 22 Nov 2024 16:59:31 -0800 (PST) Received: from devvm4158.cln0.facebook.com (2620:10d:c0a8:1b::8e35) by mail.thefacebook.com (2620:10d:c0a9:6f::237c) with Microsoft SMTP Server id 15.2.1544.11; Sat, 23 Nov 2024 00:58:59 +0000 From: Vadim Fedorenko To: Borislav Petkov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Thomas Gleixner , Yonghong Song , Vadim Fedorenko , Mykola Lysenko CC: , , Peter Zijlstra , Vadim Fedorenko , Martin KaFai Lau Subject: [PATCH bpf-next v9 2/4] bpf: add bpf_cpu_time_counter_to_ns helper Date: Fri, 22 Nov 2024 16:58:31 -0800 Message-ID: <20241123005833.810044-3-vadfed@meta.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20241123005833.810044-1-vadfed@meta.com> References: <20241123005833.810044-1-vadfed@meta.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Proofpoint-GUID: Ps-uXi1HT25woT-aelNwR2mHh6fWK-Ed X-Proofpoint-ORIG-GUID: Ps-uXi1HT25woT-aelNwR2mHh6fWK-Ed X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-05_03,2024-10-04_01,2024-09-30_01 The new helper should be used to convert deltas of values received by bpf_get_cpu_time_counter() into nanoseconds. It is not designed to do full conversion of time counter values to CLOCK_MONOTONIC_RAW nanoseconds and cannot guarantee monotonicity of 2 independent values, but rather to convert the difference of 2 close enough values of CPU timestamp counter into nanoseconds. This function is also JITted into just several instructions and adds as low overhead as possible and perfectly suits benchmark use-cases. Reviewed-by: Eduard Zingerman Acked-by: Andrii Nakryiko Signed-off-by: Vadim Fedorenko --- arch/x86/net/bpf_jit_comp.c | 27 +++++++++++++++++++++++++++ arch/x86/net/bpf_jit_comp32.c | 27 +++++++++++++++++++++++++++ include/linux/bpf.h | 1 + kernel/bpf/helpers.c | 14 +++++++++++++- 4 files changed, 68 insertions(+), 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 92431ab1a21e..d21e0ab55c94 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -11,10 +11,12 @@ #include #include #include +#include #include #include #include #include +#include #include #include #include @@ -2216,6 +2218,28 @@ st: if (is_imm8(insn->off)) break; } + if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && + imm32 == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns) && + using_native_sched_clock() && sched_clock_stable()) { + struct cyc2ns_data data; + u32 mult, shift; + + cyc2ns_read_begin(&data); + mult = data.cyc2ns_mul; + shift = data.cyc2ns_shift; + cyc2ns_read_end(); + /* imul RAX, RDI, mult */ + maybe_emit_mod(&prog, BPF_REG_1, BPF_REG_0, true); + EMIT2_off32(0x69, add_2reg(0xC0, BPF_REG_1, BPF_REG_0), + mult); + + /* shr RAX, shift (which is less than 64) */ + maybe_emit_1mod(&prog, BPF_REG_0, true); + EMIT3(0xC1, add_1reg(0xE8, BPF_REG_0), shift); + + break; + } + func = (u8 *) __bpf_call_base + imm32; if (src_reg == BPF_PSEUDO_CALL && tail_call_reachable) { LOAD_TAIL_CALL_CNT_PTR(stack_depth); @@ -3828,5 +3852,8 @@ bool bpf_jit_inlines_kfunc_call(s32 imm) { if (imm == BPF_CALL_IMM(bpf_get_cpu_time_counter)) return true; + if (imm == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns) && + using_native_sched_clock() && sched_clock_stable()) + return true; return false; } diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c index a549aea25f5f..a2069a3ee4a3 100644 --- a/arch/x86/net/bpf_jit_comp32.c +++ b/arch/x86/net/bpf_jit_comp32.c @@ -12,10 +12,12 @@ #include #include #include +#include #include #include #include #include +#include #include /* @@ -2100,6 +2102,27 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, EMIT2(0x0F, 0x31); break; } + if (imm32 == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns) && + cpu_feature_enabled(X86_FEATURE_CONSTANT_TSC)) { + struct cyc2ns_data data; + u32 mult, shift; + + cyc2ns_read_begin(&data); + mult = data.cyc2ns_mul; + shift = data.cyc2ns_shift; + cyc2ns_read_end(); + + /* move parameter to BPF_REG_0 */ + emit_ia32_mov_r64(true, bpf2ia32[BPF_REG_0], + bpf2ia32[BPF_REG_1], true, true, + &prog, bpf_prog->aux); + /* multiply parameter by mut */ + emit_ia32_mul_i64(bpf2ia32[BPF_REG_0], + mult, true, &prog); + /* shift parameter by shift which is less than 64 */ + emit_ia32_rsh_i64(bpf2ia32[BPF_REG_0], + shift, true, &prog); + } err = emit_kfunc_call(bpf_prog, image + addrs[i], @@ -2633,5 +2656,9 @@ bool bpf_jit_inlines_kfunc_call(s32 imm) { if (imm == BPF_CALL_IMM(bpf_get_cpu_time_counter)) return true; + if (imm == BPF_CALL_IMM(bpf_cpu_time_counter_to_ns) && + using_native_sched_clock() && sched_clock_stable()) + return true; + return false; } diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 6d540253cfb4..dd3c4ddfd60e 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3336,6 +3336,7 @@ u64 bpf_get_raw_cpu_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); /* Inlined kfuncs */ #if IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) u64 bpf_get_cpu_time_counter(void); +u64 bpf_cpu_time_counter_to_ns(u64 cycles); #endif #if defined(CONFIG_NET) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 23f1a1606f8b..e4d461f2e98f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3079,8 +3079,19 @@ __bpf_kfunc u64 bpf_get_cpu_time_counter(void) */ return __arch_get_hw_counter(1, vd); } -#endif +__bpf_kfunc u64 bpf_cpu_time_counter_to_ns(u64 cycles) +{ + const struct vdso_data *vd = __arch_get_k_vdso_data(); + + vd = &vd[CS_RAW]; + /* kfunc implementation does less manipulations than vDSO + * implementation. BPF use-case assumes two measurements are close + * in time and can simplify the logic. + */ + return mul_u64_u32_shr(cycles, vd->mult, vd->shift); +} +#endif __bpf_kfunc_end_defs(); BTF_KFUNCS_START(generic_btf_ids) @@ -3175,6 +3186,7 @@ BTF_ID_FLAGS(func, bpf_iter_kmem_cache_next, KF_ITER_NEXT | KF_RET_NULL | KF_SLE BTF_ID_FLAGS(func, bpf_iter_kmem_cache_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) #if IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) BTF_ID_FLAGS(func, bpf_get_cpu_time_counter, KF_FASTCALL) +BTF_ID_FLAGS(func, bpf_cpu_time_counter_to_ns, KF_FASTCALL) #endif BTF_KFUNCS_END(common_btf_ids) -- 2.43.5