From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=185.171.202.116 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792486125; b=MVT+Ei2/FL2m6eUHYhgCA7v+MIo78clBC7PgXp6MUxIbIwFPsKhGNnVJXiILPTQqCjNN BiUIBXL7qOIfKwR3dfABUnFTSrNP2k+KoODsQsqcCEhaIlgfmfYAr0gSVZkPRkuTrJjDg LDaWm9xk76kDtOui3umV1dVzgNO9RSZGrQNuQQr5uaBK6y/8qO14MKZbemp91XAVzny/X Sd8BV4hIemqI3fCErdyDl3eOgQHmUtTYgsNSstEE25RehkFoL8zlqrcOGRFkKiOJ4zl6q s5O26rOyJXNR2LXjX+YiODpCAn7yODfegRcUR6o5kJPWUMByMSgBlE8kt0KB/7gWt/w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792486125; h=DMARC-Filter:Received:Received:Received:DKIM-Signature:Mime-Version: Content-Transfer-Encoding:Content-Type:Date:Message-Id:Subject:Cc: From:To:X-Mailer:References:In-Reply-To:X-Last-TLS-Session-Version; bh=OL7xSgnMDI1XhqtDCk/Z7BVGAq+sl8BFQtpkjDJSuxM=; b=MJfcZddV7tPfUOpY/8v+EcPhP/8zqBS58KBtgtseRnRYw6utBPasD1f9MJtX3EG/cuXC we3vuzkilgzqoHjs8EbT1TUUTlZZplV1mRMfA0gnczLuny/YRbj8bzLIGh+g4EB5nTUt4 3eEt10X8bOPCK6ZpHa5YvLReoghi0KyjzXmp7ccPldz2+Yj0GYMPsvBa1xknYG49vZcfc RiyOVwO6KtD0LhA4Zv1W9vKhlnqHJNsb3C+7QSI0JZIS6RlHPIHNWiZNuXw8GzrV7OOC9 w3ePBPVfZMnJCwMAfkloDzcfXx5A2Y680J3K75nQu99cK+AVPCj2+SGSFcWavzEgl/A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass header.d=bootlin.com header.i=@bootlin.com header.a=rsa-sha256 header.s=dkim header.b=BXcTZoWS; arc=none smtp.remote-ip=185.171.202.116 Received: from smtpout-04.galae.net (smtpout-04.galae.net [185.171.202.116]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B3A22606A320 for ; Tue, 20 Oct 2026 08:48:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org B3A22606A320 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=bootlin.com header.i=@bootlin.com header.a=rsa-sha256 header.s=dkim header.b=BXcTZoWS Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-04.galae.net (Postfix) with ESMTPS id 66636C63454; Tue, 20 Oct 2026 08:49:41 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id ED09560393; Tue, 20 Oct 2026 08:48:42 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 6176F1032840C; Tue, 20 Oct 2026 10:48:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1792486121; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=OL7xSgnMDI1XhqtDCk/Z7BVGAq+sl8BFQtpkjDJSuxM=; b=BXcTZoWSa4aBKdbD593+IjWSFMzaEBpqWmMhVbP7C3hoX4IBRh3tTnYzgq+Zzny7Rij1i2 hHuIok/lc7zFrIqLHe/03WKgqMyqCa4S2Qa662GiS5m4gJbUfEBCsbRDX6C21rnOQkg8rY L9c4xKjoDbQttIUn+/NT3Sf3XRlHCRGiyYWa+uIOQldId84bSgyTEnMY1V4iArS3fRE+03 S/nu/Pzd78WwipUx7nPkfQXnDMhyfST0vVW9mKFdM1IlCCBtbZUiupOCJwGfd9r1jDZfBn x1ywd7HdcC97OJgkHIPUOauc35w4z7E8DHMnt8LLqoIAP5whMB++O6la381mdA== X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 20 Oct 2026 10:48:35 +0200 Message-Id: Subject: Re: [PATCH bpf-next v2] selftests/bpf: Time tc_edt from its first packet with data Cc: , , From: =?utf-8?q?Alexis_Lothor=C3=A9?= To: "Qiliang Yuan" , "Alexei Starovoitov" , "Daniel Borkmann" , "Andrii Nakryiko" , "Eduard Zingerman" , "Kumar Kartikeya Dwivedi" , "Martin KaFai Lau" , "Song Liu" , "Yonghong Song" , "Jiri Olsa" , "Emil Tsalapatis" , "Ihor Solodrai" , "Shuah Khan" , =?utf-8?b?QWxleGlzIExvdGhvcsOpIChlQlBGIEZvdW5kYXRpb24p?= X-Mailer: aerc 0.22.0-0-gc2f86b7abde3 References: <20261019-selftests-bpf-tc-edt-serial-v2-1-41c3813e7916@gmail.com> In-Reply-To: <20261019-selftests-bpf-tc-edt-serial-v2-1-41c3813e7916@gmail.com> X-Last-TLS-Session-Version: TLSv1.3 Hi Qiliang, On Mon Oct 19, 2026 at 8:35 AM CEST, Qiliang Yuan wrote: > tc_edt sends 1MB over a TCP connection that a BPF program shapes with > EDT, and checks that the rate it measures is within 2% of the target > rate. The transfer takes about 200ms, so the margin is about 4ms. > > The measurement starts before send_recv_data(), which first creates the > sender thread and accepts the connection. On a KASAN kernel, x86_64 VM > with 32 vCPUs, that takes 0.7ms when idle and up to 4.7ms with all > CPUs busy, while the BPF program spreads the data over 200.08ms in the > median. The test also fails without test_progs -j where everything runs > slower, e.g. on s390x and with ASAN in BPF CI. > > Have the BPF program note when the first packet with data goes out, and > start the measurement there. > > tc_edt run 100 times on the same VM, idle and with 32 busy loops in the > background, before and after this patch: > > before after > idle 0 of 100 failed 0 of 100 failed > busy loops 3 of 100 failed 0 of 100 failed > > Fixes: b0f82e7ab6fb ("selftests/bpf: integrate test_tc_edt into test_prog= s") > Signed-off-by: Qiliang Yuan I still suspect that it will not solve the flakyness for every setup and that it probably deserves a margin increase anyway, but the updated measurement looks like a reasonable improvement to me. Reviewed-by: Alexis Lothor=C3=A9 (eBPF Foundation) --=20 Alexis Lothor=C3=A9, Bootlin Embedded Linux and Kernel engineering https://bootlin.com