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 BCE6723182D for ; Thu, 8 Jan 2026 02:18:34 +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=1767838714; cv=none; b=gZ8ReEL0f2ekg89CCQy57pNjp9QuCueH+0F7lPy2mVoLdkKlHSMRXpYCDgnRT/1YMEvMtESnd7m53dTpdOL3DsPLVVaj7/0rtFIlxzrX4RPt9m/Rdb79ues2JIpMpK94sHn+1TCHT65g2dbwrrNOofqgn+92wEJYGWyX84/W5sU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767838714; c=relaxed/simple; bh=m6nzrMr5C8GMHw1NcJLXXPXSto9QlZnPkCdNACldZUY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=I9HU+EbpjbFYY0cYESm3ofk3SNZ87ZyUswlA4ZKHOnHRJxknVOWaUnZQX4wWbdloVm2IvWSz9nDo9bHrPcobF+2XpiItJkopBhzYW5lA3Z6jE4ZVt3iyGm5zwercDlVLh8cA8iOetpsxcv37Qk3pqGcUGbsYjpPcKX7fxsXquy0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nkxeG/E4; 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="nkxeG/E4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38431C4CEF1; Thu, 8 Jan 2026 02:18:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767838714; bh=m6nzrMr5C8GMHw1NcJLXXPXSto9QlZnPkCdNACldZUY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nkxeG/E4NszmSFajVyOIVaAmBcHpSCcEBkEfr6MIFNXg0mdhBBPXR9Qa0wx1SXgBv ihqC+lMJrIt/PtEqhbpiESdPKt1s2g71RLpD8lGrzW9zqGcZDbytIAEfZdNoCf2/q9 rm/BmNTUOYNOKbUAs5wNdmiclckiOlhNzSCwpB5ZFbtX7tlveDHSFEEJQy4n6JeCJj FBKxWNFd5HMmcJb8/PgUiIF1APsry1pWWNYQ98bvIqBrfPRQmmYlzd+UwW0wNLHRSi aPSlQ3PgS0M5uYwglriPO1vzngyZwOXcTm5MbiQCUo8ecwKi/MjJgm9eW5okT9zUzG n06M5yCTE4ccg== Date: Wed, 7 Jan 2026 18:18:33 -0800 From: Jakub Kicinski To: Cong Wang Cc: Stephen Hemminger , 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: <20260107181833.692a9ea1@kernel.org> In-Reply-To: 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 Wed, 7 Jan 2026 15:33:53 -0800 Cong Wang 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. > > In patch 6/8, I added "Test PRIO with NETEM duplication", which installs > netem Qdisc as a child and leaf of root prio qdisc. > > Or am I misunderstanding it? Does something automatically validates that backlog is 0 when qdisc is destroyed? The test itself only checks: "matchPattern": "Sent \\d+ bytes (\\d+) pkt",