From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5586BC433EF for ; Mon, 18 Jul 2022 14:46:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234091AbiGROql (ORCPT ); Mon, 18 Jul 2022 10:46:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229647AbiGROql (ORCPT ); Mon, 18 Jul 2022 10:46:41 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A4A72BCE for ; Mon, 18 Jul 2022 07:46:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658155600; x=1689691600; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=ew4Wtu4O4sQJvl9BxuElFGEFRvg43uMfAM4rlKC3aiM=; b=ESsaLdsPDUbhP7njMecA4uW3xNHYb6PnOohPfHtsKiecs45QpUR3SHvg kysspKDQkvfF/1/B6FpyQP8VOFVF5VNnhjy8ryHnuPjEgoK80MQlsAzbz mgfwWURJZ3wfnaP11VwBanl7+6BPUdjo2LKaY3gs4n0G1JIMzsclG+B2m PKRr+Pqq9IPnh0AjqZVfiMxazj8YU3QvsyN29IAsg7xvyGQhM8sqi4MTe t/y/Ls7I3qHzkijtvs6cpvK04nzFchvOA3rLGCE3A1sJH80yKZhfklYo/ Z6msdi2ujYb3HbzKQgfru7RZFaADNsq0yDj1rKguwdTguJgm/xuZP4AJ1 w==; X-IronPort-AV: E=McAfee;i="6400,9594,10412"; a="286257313" X-IronPort-AV: E=Sophos;i="5.92,281,1650956400"; d="scan'208";a="286257313" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jul 2022 07:46:39 -0700 X-IronPort-AV: E=Sophos;i="5.92,281,1650956400"; d="scan'208";a="572433143" Received: from npande-mobl1.amr.corp.intel.com (HELO vcostago-mobl3) ([10.212.52.138]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jul 2022 07:46:37 -0700 From: Vinicius Costa Gomes To: Ferenc Fejes , "netdev@vger.kernel.org" Cc: "jesse.brandeburg@intel.com" , "anthony.l.nguyen@intel.com" Subject: Re: igc: missing HW timestamps at TX In-Reply-To: References: Date: Mon, 18 Jul 2022 11:46:34 -0300 Message-ID: <87tu7emqb9.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Ferenc, Ferenc Fejes writes: > (Ctrl+Enter'd by mistake) > > My question here: is there anything I can quickly try to avoid that > behavior? Even when I send only a few (like 10) packets but on fast > rate (5us between packets) I get missing TX HW timestamps. The receive > side looks much more roboust, I cannot noticed missing HW timestamps > there. There's a limitation in the i225/i226 in the number of "in flight" TX timestamps they are able to handle. The hardware has 4 sets of registers to handle timestamps. There's an aditional issue that the driver as it is right now, only uses one set of those registers. I have one only briefly tested series that enables the driver to use the full set of TX timestamp registers. Another reason that it was not proposed yet is that I still have to benchmark it and see what is the performance impact. If you are feeling adventurous and feel like helping test it, here is the link: https://github.com/vcgomes/net-next/tree/igc-multiple-tstamp-timers-lock-new Cheers, -- Vinicius