From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f52.google.com (mail-qv1-f52.google.com [209.85.219.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D3E71269D1B; Tue, 18 Feb 2025 14:25:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739888716; cv=none; b=KscCqhYZ4Xw7SCYVpOoKI1iIIa/4kNAeO9VrwCnQTLyflWSpDzAJgGmcD4480n+r7/rZTXmt6Uk9nb8r4PeYOjcyH4295zgIaEnbpg0TO6BOmJcYV/JGawLsjkcFyH85oPCCsyspf46qfcZ1Mx9O+Qfr4mJw/RXtPssnNzGNHWU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739888716; c=relaxed/simple; bh=lxwLjCBJajtWzaRsy8pRrf11hv7+sqzFijfOOsIMNiU=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: Mime-Version:Content-Type; b=lY1mHeZQ/4gREiWQCmcBm7Nzc8ObAbNWhyR5WnxFF5VeCqHUSZ5FxtfP3KELZv1ngexv3d3kDEA7pb4yeY+tjb2vqSh1d5qUVFJOiABlBe8TeviVvSvigm1z+GpSM/GQoRQ4dVOajnQ/pHFpuT/sb5jUrk3fpWFXb8z2haDN7C0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=hwjejwI+; arc=none smtp.client-ip=209.85.219.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hwjejwI+" Received: by mail-qv1-f52.google.com with SMTP id 6a1803df08f44-6e6698667c7so48924676d6.2; Tue, 18 Feb 2025 06:25:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1739888714; x=1740493514; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=SjlgcMMqJDdeuMoyqpKeWIayNuR9Egse6jJeToK8tgA=; b=hwjejwI+CEhAqAgk+CuGnplGTQCcCOLloeXJGhG5IwKWNotqAVdXVPs2UbSsdN7cD1 ZnpH6w3cTI90idECJ06Dx+W2XgS5vqRrOIeyAhlkmMv7j1ucwy+5tUNVwnMpD3vy76z1 mdZamUONFity9QRaNHKySPdnelolsZuWm6X80h9SSn1kQkXI/4p263PXH6lxZ+949woU duq74uMwniTX23rbPHea0QtsAoIPCikefgTiLTZelIlshS1L5bKTpbAOV8S4XzCbwAfW Caf1JX5NZ13I1+5J4rAtwa4HhuV6fnk1P7PRWuvRVN0u/Ca+rhPYgpX6V+e+OybAgKt6 eWaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739888714; x=1740493514; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=SjlgcMMqJDdeuMoyqpKeWIayNuR9Egse6jJeToK8tgA=; b=wfymXtR40MVYlrgso4dmsjGJLPzNs5Aucb6k8/ZUXkhyUf3+tnErSyKeQeVIWL6AZA HgnL1lai4tr3WndrMbk11Fpu/V85hGDODP7I8yKNg+z1WkZZo52/wYoQC2lLu0zWU7Vk RSuTo4Z3JENcarhIiPsfIO187m1p7pb55Wu+Ab80nokSob1+DnXgnzY7Dvx9QO3dUMvY OpUABptluLsjoSBslSi0qNqNkQ2wWIn8Vv76j6UsdDEmZHL+tDJmOvjOASVkjjzV+uiJ EZ3qMjbY+3sf+aYBOzdNOf7/f2jEqKywAPgm7A/Z+y495xjj1VVz23qX8gtQXlt4b3PU rL0g== X-Forwarded-Encrypted: i=1; AJvYcCXMAb5QheEiJzBaA8m5M3ki1x+MyNnpsLv/T2FhhImXqJ4rYExtMD2xHt5wFrdJOwyCD7ZAwVU=@vger.kernel.org X-Gm-Message-State: AOJu0YyMFQrZBo3EuFHBgANkZko9NZyNdlaHdrfBOCWx0fK629bdv8x2 JygZJUFgmkhwwMGCxuyy7woAWyMNJNNf+aXAtvJLsOPx75vndUC/ X-Gm-Gg: ASbGncs9HMpqP5QVVqsNa0J24Tom6bdoTdriddEiDSSJrwriTE3LiZcIa2WR1P8bflY iUxhaF+DtnsabIg33JeIuYZ1xxE0e+XOpvNqE01cHcXJCSI1AtViC/CzBTjJ1syrvvqCRur1BC5 vqdg/qvEUxM6AdME19/40Fl7pW/3Qjndi8FZ4jthBHEsVzXJCnmciwzKursIWPDKkhgYehGnTua WtPIOxzFLERYVmAhK9uLDWOp6OvC6She5yygka4GqN7LzqtbWrgp+Iwqs77e8kUIC2ByGVRqa1m goHzmEeID9t2DVeZbmK/ckYUi0fbpUGpKV0UKNBRH0iKyydsB3OUE9BqI/vztL4= X-Google-Smtp-Source: AGHT+IHu7PdU59at4kGPYkzhaNI9dPdA+7XpebIwViRcfka6VwouB3Jp+J76s2y68q8u0gZHZstvmQ== X-Received: by 2002:ad4:5f0a:0:b0:6e4:4393:de7 with SMTP id 6a1803df08f44-6e66cc8951bmr211066306d6.2.1739888713725; Tue, 18 Feb 2025 06:25:13 -0800 (PST) Received: from localhost (15.60.86.34.bc.googleusercontent.com. [34.86.60.15]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c07c5f35bdsm669157985a.7.2025.02.18.06.25.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Feb 2025 06:25:13 -0800 (PST) Date: Tue, 18 Feb 2025 09:25:12 -0500 From: Willem de Bruijn To: Jason Xing , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, willemdebruijn.kernel@gmail.com, willemb@google.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, ykolal@fb.com Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, Jason Xing Message-ID: <67b49848ec47c_10d6a329425@willemb.c.googlers.com.notmuch> In-Reply-To: <20250218050125.73676-13-kerneljasonxing@gmail.com> References: <20250218050125.73676-1-kerneljasonxing@gmail.com> <20250218050125.73676-13-kerneljasonxing@gmail.com> Subject: Re: [PATCH bpf-next v12 12/12] selftests/bpf: add simple bpf tests in the tx path for timestamping feature Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Jason Xing wrote: > BPF program calculates a couple of latency deltas between each tx > timestamping callbacks. It can be used in the real world to diagnose > the kernel behaviour in the tx path. > > Check the safety issues by accessing a few bpf calls in > bpf_test_access_bpf_calls() which are implemented in the patch 3 and 4. > > Check if the bpf timestamping can co-exist with socket timestamping. > > There remains a few realistic things[1][2] to highlight: > 1. in general a packet may pass through multiple qdiscs. For instance > with bonding or tunnel virtual devices in the egress path. > 2. packets may be resent, in which case an ACK might precede a repeat > SCHED and SND. > 3. erroneous or malicious peers may also just never send an ACK. > > [1]: https://lore.kernel.org/all/67a389af981b0_14e0832949d@willemb.c.googlers.com.notmuch/ > [2]: https://lore.kernel.org/all/c329a0c1-239b-4ca1-91f2-cb30b8dd2f6a@linux.dev/ > > Signed-off-by: Jason Xing Reviewed-by: Willem de Bruijn