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 07E0FCA6B for ; Thu, 8 Jan 2026 03:25:12 +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=1767842713; cv=none; b=WA4nGoV6wX8aigEhcEeA7uiNEiJdl/efErPf6RiDlk3eK0OP7A2ofE+FVGIw3OCNoth3GuRSbu/HblzcB4qkXUe4sfHrJEMIVK0fzoabNg/PwXt5YgkQuJ/u4msL6EeIFrEVItEOBpnhPwAnIO6fwIqbfLpWVMu3bsHTb9ps31Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767842713; c=relaxed/simple; bh=l6bN91X2DSVBOPicQ24dGdWUQRFvPPXfvT8/S7OVgys=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=A9GbNyOBX1ANx97+D2R3rRUnXyfIlfX0e88z6UMzOXSHabriodJV5loVDq1Sz3o+tCJAVCE9QVvBe4vPQJ0AehPLZLO11nO/k7EQrVq+GiF7FGOo7H/+QawtcTRDWvO5tQ0wXYDiqPNvaG9pq04kVlyuVyOjvT31FpuKsuKSfno= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=A6cXgZ9g; 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="A6cXgZ9g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5214DC116C6; Thu, 8 Jan 2026 03:25:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767842712; bh=l6bN91X2DSVBOPicQ24dGdWUQRFvPPXfvT8/S7OVgys=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=A6cXgZ9g7E8oGdyzxwXg7BfwKJ0Bb3ZZPj69ZBy/hV9wSlwaFBycYi5xH19YhIqOs 3Kg1M1KeZw64FIY5kR37Q9pKNpn57ttsXVKRNIrLk87W3bAXJQCgx9zRQ9JYd9/15H UPk2nf/NkV6JOTn2m7u/m0CrAzBl+yIFNcwr2lhr+ZVgGkzW1OAKz2aRGEt3NeCea0 ISkscfXOX/blG86ZwkLtsSLLRWPu0VTXKYm7Yl9Lpu1F4wRCTXjDQc9by78xb+BTX1 zNbz2Vw4AHlWVQE+t03xBhBtNZjurHBpvODMQ+Te/jtZn593bARnthCkuNM1vwh2Ej Mi8TZ7v91hC6Q== Date: Wed, 7 Jan 2026 19:25:11 -0800 From: Jakub Kicinski To: Willem de Bruijn Cc: Willem de Bruijn , "netdev@vger.kernel.org" Subject: Re: [TEST] txtimestamp.sh pains after netdev foundation migration Message-ID: <20260107192511.23d8e404@kernel.org> In-Reply-To: References: <20260107110521.1aab55e9@kernel.org> 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 Thanks for investigating! On Wed, 07 Jan 2026 19:19:53 -0500 Willem de Bruijn wrote: > 17 out of 20 happen in the first SND-USR calculation. > One representative example: > > # 7.11 [+0.00] test SND > # 7.11 [+0.00] USR: 1767443466 s 155019 us (seq=0, len=0) > # 7.19 [+0.08] ERROR: 18600 us expected between 10000 and 18000 > # 7.19 [+0.00] SND: 1767443466 s 173619 us (seq=0, len=10) (USR +18599 us) > # 7.20 [+0.00] USR: 1767443466 s 243683 us (seq=0, len=0) > # 7.27 [+0.07] SND: 1767443466 s 253690 us (seq=1, len=10) (USR +10006 us) > # 7.27 [+0.00] USR: 1767443466 s 323746 us (seq=0, len=0) > # 7.35 [+0.08] SND: 1767443466 s 333752 us (seq=2, len=10) (USR +10006 us) > # 7.35 [+0.00] USR: 1767443466 s 403811 us (seq=0, len=0) > # 7.43 [+0.08] SND: 1767443466 s 413817 us (seq=3, len=10) (USR +10006 us) > # 7.43 [+0.00] USR-SND: count=4, avg=12154 us, min=10006 us, max=18599 us Hm, that's the first kernel timestamp vs the timestamp in user space? I wonder if we could catch this by re-taking the user stamp after sendmsg() returns, if >1msec elapsed something is probably wrong (we got scheduled out before having a chance to complete the send?) > These are just outside the bounds of 18000. So increasing the > tolerance in txtimestamp.sh will probably mitigate them. All 17 > would have passed with the following change. > > - local -r args="$@ -v 10000 -V 60000 -t 8000 -S 80000" > + local -r args="$@ -v 10000 -V 60000 -t 8000 -S 100000" > > Admittedly a hacky workaround that will only reduce the rate. > > It's interesting that > > - every time it is the first of the four measurements that fails. > - it never seems to occur for TCP sockets. FWIW: https://netdev-ctrl.bots.linux.dev/logs/vmksft/net/results/449080/13-txtimestamp-sh/stdout but that could be related to some bad patch..