From mboxrd@z Thu Jan 1 00:00:00 1970 From: joerg.krause@embedded.rocks (=?ISO-8859-1?Q?J=F6rg_Krause?=) Date: Thu, 13 Oct 2016 21:43:00 +0200 Subject: Low network throughput on i.MX28 In-Reply-To: <20161013084807.6a231fdb@ipc1.ka-ro> References: <1476313753.2065.11.camel@embedded.rocks> <20161013084807.6a231fdb@ipc1.ka-ro> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Lothar, Am 13. Oktober 2016 08:48:07 MESZ, schrieb "Lothar Wa?mann" : >Hi, > >On Thu, 13 Oct 2016 01:09:13 +0200 J?rg Krause wrote: >> Hi, >> >> I am using a custom i.MX28 board similar to the i.MX28-EVK. For Wi-Fi >> the board assembles a BCM43362 from Broadcom and for Ethernet a >> LAN8720A from Microchip. The board is running mainline Linux 4.7. >> >> While both, wireless and wired network interfaces work, the TCP >> throughput measured with iperf is low. >> >> The bandwith for Ethernet is between 20-30 MBits/sec and for WLAN is >> about 4-5 MBits/sec. >> >> There exists an Application Note "i.MX28 Ethernet Performance on >> Linux" [1] which shows a bandwith of > 60 MBits/sec. A user an the >NXP >> forum [2] told he achieved 20 MBits/sec with some Qualcom chip. >> >> Note, that these values are most probably measured with the legacy >> Linux Kernel 2.6.35 from NXP. >> >> Does anybody has done throughput tests on i.MX28 with mainline >Kernel? >> If so, what are the results? What might be the bottleneck? >> > >This is the iperf output on a TX28 with current mainline kernel >(4.8.0-rc5): >------------------------------------------------------------ >Client connecting to 192.168.100.1, TCP port 5001 >TCP window size: 43.8 KByte (default) >------------------------------------------------------------ >[ 3] local 192.168.100.56 port 60325 connected with 192.168.100.1 port >5001 >[ ID] Interval Transfer Bandwidth >[ 3] 0.0-10.0 sec 57.5 MBytes 48.2 Mbits/sec > >You might check your kernel DEBUG configs (especially >CONFIG_DEBUG_PAGEALLOC). Thanks for sharing the iperf output. What LAN transceiver does the TX28 has assembled? I checked the config and is has no DEBUG_PAGEALLOC enabled and no DEBUG options related to network. Best regards J?rg Krause