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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F426C28CC0 for ; Fri, 31 May 2019 01:47:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 02A4026264 for ; Fri, 31 May 2019 01:47:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726855AbfEaBq4 (ORCPT ); Thu, 30 May 2019 21:46:56 -0400 Received: from mailgw02.mediatek.com ([1.203.163.81]:9264 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726372AbfEaBq4 (ORCPT ); Thu, 30 May 2019 21:46:56 -0400 X-UUID: 05a641429e3146f69f07f2838f987952-20190531 X-UUID: 05a641429e3146f69f07f2838f987952-20190531 Received: from mtkcas32.mediatek.inc [(172.27.4.253)] by mailgw02.mediatek.com (envelope-from ) (mailgw01.mediatek.com ESMTP with TLS) with ESMTP id 578061618; Fri, 31 May 2019 09:46:50 +0800 Received: from MTKCAS36.mediatek.inc (172.27.4.186) by MTKMBS31N2.mediatek.inc (172.27.4.87) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 31 May 2019 09:46:47 +0800 Received: from [10.17.3.153] (172.27.4.253) by MTKCAS36.mediatek.inc (172.27.4.170) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 31 May 2019 09:46:44 +0800 Message-ID: <1559267203.24897.101.camel@mhfsdcap03> Subject: Re: [PATCH 3/4] net: stmmac: modify default value of tx-frames From: biao huang To: Andrew Lunn , Jose Abreu CC: Giuseppe Cavallaro , Alexandre Torgue , Maxime Coquelin , Matthias Brugger , , , , , , , , Date: Fri, 31 May 2019 09:46:43 +0800 In-Reply-To: <20190530125832.GB22727@lunn.ch> References: <1559206484-1825-1-git-send-email-biao.huang@mediatek.com> <1559206484-1825-4-git-send-email-biao.huang@mediatek.com> <20190530125832.GB22727@lunn.ch> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Andrew, On Thu, 2019-05-30 at 14:58 +0200, Andrew Lunn wrote: > On Thu, May 30, 2019 at 04:54:43PM +0800, Biao Huang wrote: > > the default value of tx-frames is 25, it's too late when > > passing tstamp to stack, then the ptp4l will fail: > > > > ptp4l -i eth0 -f gPTP.cfg -m > > ptp4l: selected /dev/ptp0 as PTP clock > > ptp4l: port 1: INITIALIZING to LISTENING on INITIALIZE > > ptp4l: port 0: INITIALIZING to LISTENING on INITIALIZE > > ptp4l: port 1: link up > > ptp4l: timed out while polling for tx timestamp > > ptp4l: increasing tx_timestamp_timeout may correct this issue, > > but it is likely caused by a driver bug > > ptp4l: port 1: send peer delay response failed > > ptp4l: port 1: LISTENING to FAULTY on FAULT_DETECTED (FT_UNSPECIFIED) > > > > ptp4l tests pass when changing the tx-frames from 25 to 1 with > > ethtool -C option. > > It should be fine to set tx-frames default value to 1, so ptp4l will pass > > by default. > > Hi Biao > > What does this do to the number of interrupts? Do we get 25 times more > interrupts? Have you done any performance tests to see if this causes > performance regressions? Yes, it seems tx-frames=25 can reduce interrupts. But the tx interrupt is handled in napi now, which will disable/enable tx interrupts at the beginning/ending of napi flow. Here is the test result on our platform: tx-frames=1 tx-frames=25 irq number 478514 393750 performance 904Mbits/sec 902Mbits/sec commands for test: "cat /proc/interrupts | grep eth0" "iperf3 -c ipaddress -w 256K -t 60" Thanks to napi, the interrupts will not grow 25 times more(almost the same level), and no obvious performance degradation. Is there anybody can double check the performance with tx-frames = 0 or 25? > > Andrew Thanks. Biao