From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 5E57C214204 for ; Thu, 21 Aug 2025 14:51:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755787903; cv=none; b=euTd21uhbDrXqfVWdPXotc2+PguJbF2fAfi019h5blDf6crTV8dRf9GQNNnkxPu5raKC358kmvr0QxSh8BVMSQMDhfgOXZ3fMrxvep26yzru3IQiDcl5TGeKi4DNU3jEPT/D2F7VmKp+BCbxbfRNmMtYPBpDV9upaw03eR9TRqg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755787903; c=relaxed/simple; bh=haGeC4GC3hxJ6JbqWzcnLgrLFTcjziUEqF5OO/4+17g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=u3MDS5dLgvwSh07EFC4wGErXvHsjAAuZsMgZ8OtzPXLCWLrq1zAdveU1tfjwJ0QhM1P6KIGmoJLWNX0qilhP1e1ZMXkUc0QX/kelRwxmhnxBcvU/rohHWHjoJwHnklMtVhqTM6pjVWlvyvozmrziToDnb4UsXU6OVWKTa6uvgXw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=IQFcKtcF; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IQFcKtcF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755787901; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rr9rUoIkr1nx8JPvQgy7YChPIsLZS2L4L5UXWNYbAxw=; b=IQFcKtcF+nSydOs59Vl9GFF+H1PvrNXA4hL1lBfU67xvBvbTXTiORi6zMx5Yt/7gi2xK7u BO0bxm+q3T6SQdTX/heCylDj0bro+nabW6EhmzCrbiMOLblAO/XZptM2ssjtX5EYRD615w xFYt0FmDIM2QyOeckTXk+MDV/XkGP+c= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-470-JBwv4IN1NdmZ4D-jFOQ2Bw-1; Thu, 21 Aug 2025 10:51:37 -0400 X-MC-Unique: JBwv4IN1NdmZ4D-jFOQ2Bw-1 X-Mimecast-MFC-AGG-ID: JBwv4IN1NdmZ4D-jFOQ2Bw_1755787895 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C259D19541BD; Thu, 21 Aug 2025 14:51:34 +0000 (UTC) Received: from localhost (unknown [10.43.135.229]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B836F3001453; Thu, 21 Aug 2025 14:51:30 +0000 (UTC) Date: Thu, 21 Aug 2025 16:51:28 +0200 From: Miroslav Lichvar To: Kurt Kanzenbach Cc: Jacob Keller , Tony Nguyen , Przemek Kitszel , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Richard Cochran , Vinicius Costa Gomes , Sebastian Andrzej Siewior , intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org Subject: Re: [Intel-wired-lan] [PATCH iwl-next] igb: Retrieve Tx timestamp directly from interrupt Message-ID: References: <20250815-igb_irq_ts-v1-1-8c6fc0353422@linutronix.de> <81c1a391-3193-41c6-8ab7-c50c58684a22@intel.com> <87ldncoqez.fsf@jax.kurt.home> <87cy8ooji5.fsf@jax.kurt.home> 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-Disposition: inline In-Reply-To: <87cy8ooji5.fsf@jax.kurt.home> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On Thu, Aug 21, 2025 at 04:08:02PM +0200, Kurt Kanzenbach wrote: > On Thu Aug 21 2025, Miroslav Lichvar wrote: > >> >> Without the patch: > >> >> NTP daemon TX timestamps : 35835 > >> >> NTP kernel TX timestamps : 1410956 > >> >> NTP hardware TX timestamps : 581575 > >> >> > >> >> With the patch: > >> >> NTP daemon TX timestamps : 476908 > >> >> NTP kernel TX timestamps : 646146 > >> >> NTP hardware TX timestamps : 412095 > > With the new patch at 200000 requests per second: > > NTP daemon TX timestamps : 192404 > > NTP kernel TX timestamps : 1318971 > > NTP hardware TX timestamps : 418805 > Here's what I can see in the traces: In the current implementation, the > kworker runs directly after the IRQ on the *same* CPU. With the AUX > worker approach the kthread can be freely distributed to any other > CPU. This in turn involves remote wakeups etc. > > You could try to pin the PTP AUX worker (e.g. called ptp0) with taskset > to the same CPU where the TS IRQs are processed. That might help to get > the old behavior back. Adjusting the priority is not necessary, both the > kworker and AUX thread run with 120 (SCHED_OTHER, nice value 0) by > default. Yes, that helps! The server timestamping stats now show: NTP daemon TX timestamps : 32902 NTP kernel TX timestamps : 1479293 NTP hardware TX timestamps : 520146 And the maximum response rate is only about 2-3% lower, so that looks good to me. Thanks, -- Miroslav Lichvar