From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: FEC performance degradation with certain packet sizes Date: Tue, 21 Jan 2014 18:49:10 +0100 Message-ID: <201401211849.10113.marex@denx.de> References: <528F50AE.3030804@digi.com> <52B45BD2.2060306@digi.com> <45804b55ce704164bc054d4275801153@BLUPR03MB373.namprd03.prod.outlook.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Hector Palacios , "netdev@vger.kernel.org" , "Fabio.Estevam@freescale.com" , "shawn.guo@linaro.org" , "l.stach@pengutronix.de" , "Frank.Li@freescale.com" , "bhutchings@solarflare.com" , "davem@davemloft.net" To: "fugang.duan@freescale.com" Return-path: Received: from mail-out.m-online.net ([212.18.0.9]:56648 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754942AbaAURtO (ORCPT ); Tue, 21 Jan 2014 12:49:14 -0500 In-Reply-To: <45804b55ce704164bc054d4275801153@BLUPR03MB373.namprd03.prod.outlook.com> Sender: netdev-owner@vger.kernel.org List-ID: On Monday, December 23, 2013 at 03:52:20 AM, fugang.duan@freescale.com wrote: > From: Hector Palacios > Sent: Friday, December 20, 2013 11:02 PM > > >To: Duan Fugang-B38611; Marek Vasut; netdev@vger.kernel.org > >Cc: Estevam Fabio-R49496; shawn.guo@linaro.org; l.stach@pengutronix.de; Li > >Frank-B20596; bhutchings@solarflare.com; davem@davemloft.net > >Subject: Re: FEC performance degradation with certain packet sizes > > > >Dear Andy, > > > >On 12/20/2013 04:35 AM, fugang.duan@freescale.com wrote: > >> [...] > >> > >> I can reproduce the issue on imx6q/dl platform with freescale internal > >> kernel > > > >tree. > > > >> This issue must be related to cpufreq, when set scaling_governor to > > > >performance: > >> echo performance > > >> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > >> > >> And then do NPtcp test, the result as below: > >> 24: 99 bytes 5 times --> 9.89 Mbps in 76.40 usec > >> 25: 125 bytes 5 times --> 12.10 Mbps in 78.80 usec > >> 26: 128 bytes 5 times --> 12.27 Mbps in 79.60 usec > >> 27: 131 bytes 5 times --> 12.80 Mbps in 78.10 usec > >> 28: 189 bytes 5 times --> 18.00 Mbps in 80.10 usec > >> 29: 192 bytes 5 times --> 18.31 Mbps in 80.00 usec > >> 30: 195 bytes 5 times --> 18.41 Mbps in 80.80 usec > >> 31: 253 bytes 5 times --> 23.34 Mbps in 82.70 usec > >> 32: 256 bytes 5 times --> 23.91 Mbps in 81.70 usec > >> 33: 259 bytes 5 times --> 24.19 Mbps in 81.70 usec > >> 34: 381 bytes 5 times --> 33.18 Mbps in 87.60 usec > >> 35: 384 bytes 5 times --> 33.87 Mbps in 86.50 usec > >> 36: 387 bytes 5 times --> 34.41 Mbps in 85.80 usec > >> 37: 509 bytes 5 times --> 42.72 Mbps in 90.90 usec > >> 38: 512 bytes 5 times --> 42.60 Mbps in 91.70 usec > >> 39: 515 bytes 5 times --> 42.80 Mbps in 91.80 usec > >> 40: 765 bytes 5 times --> 56.45 Mbps in 103.40 usec > >> 41: 768 bytes 5 times --> 57.11 Mbps in 102.60 usec > >> 42: 771 bytes 5 times --> 57.22 Mbps in 102.80 usec > >> 43: 1021 bytes 5 times --> 70.69 Mbps in 110.20 usec > >> 44: 1024 bytes 5 times --> 70.70 Mbps in 110.50 usec > >> 45: 1027 bytes 5 times --> 69.59 Mbps in 112.60 usec > >> 46: 1533 bytes 5 times --> 73.56 Mbps in 159.00 usec > >> 47: 1536 bytes 5 times --> 72.92 Mbps in 160.70 usec > >> 48: 1539 bytes 5 times --> 73.80 Mbps in 159.10 usec > >> 49: 2045 bytes 5 times --> 93.59 Mbps in 166.70 usec > >> 50: 2048 bytes 5 times --> 94.07 Mbps in 166.10 usec > >> 51: 2051 bytes 5 times --> 92.92 Mbps in 168.40 usec > >> 52: 3069 bytes 5 times --> 123.43 Mbps in 189.70 usec > >> 53: 3072 bytes 5 times --> 123.68 Mbps in 189.50 usec > > > >You are right. Unfortunately, this does not work on i.MX28 (at least for > >me). Couldn't it be that the cpufreq is masking the problem on the i.MX6? > > > >Best regards, > >-- > >Hector Palacios > > I reproduce the issue on imx28 evk platform, imx28 has no specific cpufreq > driver. In kernel 3.13, the ethernet driver is almost the same for imx28 > and imx6 since they use the Same enet IP, but imx6 enet IP have some > evolution. > > Now I don't know the cause. When I am free, I will dig out it. Hi! Is there any progress on this issue ? Did you manage to find anything out please? Best regards, Marek Vasut