From mboxrd@z Thu Jan 1 00:00:00 1970 From: mans@mansr.com (=?iso-8859-1?Q?M=E5ns_Rullg=E5rd?=) Date: Wed, 02 Aug 2017 17:43:05 +0100 Subject: [RFC PATCH v2 0/2] nb8800 suspend/resume support In-Reply-To: (Mason's message of "Wed, 2 Aug 2017 18:39:08 +0200") References: <33d1ab47-6098-5e3f-8a3c-f72626d07113@free.fr> <9e8e12b1-74e2-8323-ec16-eebda46b2a3d@free.fr> <6906dccf-bec9-0fc8-a34a-c39c05ada917@free.fr> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Mason writes: > On 02/08/2017 18:10, M?ns Rullg?rd wrote: > >> Mason writes: >> >>> On 02/08/2017 17:56, M?ns Rullg?rd wrote: >>> >>>> What does the tango5 do if you flood it with packets faster than the >>>> kernel can keep up with? That would make it hit the end of the rx >>>> chain, which is apparently what makes it miserable with the current dma >>>> stop code. >>> >>> The simplest way to test this would be sending tiny packets >>> as fast as possible, right? So ping -f on a GigE link should >>> fit the bill? >> >> ping -f is limited to 100 packets per second. Use something like iperf >> in UDP mode instead. > > ping -f can go 100 times faster than 100 pps: > > # ping -f -q -c 150000 -s 300 172.27.64.45 > PING 172.27.64.45 (172.27.64.45) 300(328) bytes of data. > > --- 172.27.64.45 ping statistics --- > 150000 packets transmitted, 150000 received, 0% packet loss, time 15035ms > rtt min/avg/max/mdev = 0.065/0.084/0.537/0.014 ms, ipg/ewma 0.100/0.087 ms > > 150,000 packets in 15 seconds = 10,000 pps > > (172.27.64.45 is the tango5 board) > > Ergo, dealing with 10,000 packets per second does not hose RX. ping -f goes as fast as the other end replies or 100 per second, whichever is higher, so says the man page. -- M?ns Rullg?rd