From mboxrd@z Thu Jan 1 00:00:00 1970 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 CE7374C92 for ; Sun, 4 Jan 2026 19:19:13 +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=1767554353; cv=none; b=qhjH3CmmnN/SncvpH+0QXKtQmI18BdtS/DqZM5wpga0MfuCBs9tMywBeUbajEBk/M70bvx/eB7UFCrqGvAEsUJHmot1mnZRljIP01kmxf0KbrtCrcW1597RUE2yCkEcghGgwBTxkUKwGKNtCEJGDC5IXnG6JDXIpPh15Fu9mKXk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767554353; c=relaxed/simple; bh=HdmQKswoZx8azX9NuRqWZS3ubjazjBKaK9jb8oq3ATE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=bF69f0S2rYqeXqnrKFrzp1QKg8YjSFYCXQwq9a/cOWkUOnj8np5vLG69qoZWcGD02tNNkBl4je7bPEKiyiiJWAaUF+JBIvJb2mlDMdthEpgYCxzwL2bq6RJ66aJ2qbkeM4YfF5BrEDiUD/DDXX8IQIQi2YOwSZUq5KTBG9CzTNk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sbz24gjy; 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="sbz24gjy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E24BC4CEF7; Sun, 4 Jan 2026 19:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767554353; bh=HdmQKswoZx8azX9NuRqWZS3ubjazjBKaK9jb8oq3ATE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=sbz24gjyPYJd6vZbP8fp2xewgM2Hb7taxO0OdGMsjk9e0UioyycsTu3vUlwi6K6jF +7Df6G3YJ1mASJ3AxIpGGw8qFbgzQrK4+sWfU47Tf42XsWua/FuyEnl6E9T6A2GSCq DEBdeYuJZjHVVIRRqKfPOHcFaPLjtTKAc/0mFol/Bgtnm0EoRwQuw+WTvw7nxs5j3j PgA571POhldUAmqk9V6UMZAzvdrRCVWjSQFNWl7tA8aILaM3qo4+ikxnjh75o1KnDY DjwNnNcxSIyM/ClaMPazZ7xHvRSFElsET1dZlb0mjcYCIqoZMh5xyOAj4fYCZlgHJf qH6FraqJgwXzg== Date: Sun, 4 Jan 2026 11:19:12 -0800 From: Jakub Kicinski To: Stephen Hemminger Cc: Cong Wang , netdev@vger.kernel.org, William Liu , Savino Dicanosa Subject: Re: [Patch net v6 4/8] net_sched: Implement the right netem duplication behavior Message-ID: <20260104111912.66940630@kernel.org> In-Reply-To: <20251230092850.43251a09@phoenix.local> References: <20251227194135.1111972-1-xiyou.wangcong@gmail.com> <20251227194135.1111972-5-xiyou.wangcong@gmail.com> <20251230092850.43251a09@phoenix.local> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 30 Dec 2025 09:28:50 -0800 Stephen Hemminger wrote: > It is worth testing for the case where netem is used as a leaf qdisc. > I worry that this could cause the parent qdisc to get accounting wrong. > I.e if HTB calls netem and netem queues 2 packets, the qlen in HTB > would be incorrect. Indeed, presumably backlog should be corrected with qdisc_tree_reduce_backlog() ? Either way it'd be great to add / adjust some test cases to confirm backlogs are 0 after the traffic stopped.