Reco <recovery...@gmail.com> wrote: > On Fri, 19 Jun 2015 20:38:12 +0200 Sven Hartge <s...@svenhartge.de> wrote:
>> Maybe the USB hardware implementation is better in the N900? The one >> in the Pi is quite bad and finicky. > I happen to have Pi too. Not that I need an NFS server on it, NFS > client is sufficient for my needs, but still. >> In addition to that, data transfer via USB is quite CPU-intensive, as >> Petter wrote and overwhelms the single CPU core of the Pi if it needs to >> drive the SD card at the same time. > Hm. I plugged an Ethernet cable into it, read and wrote a big file via > NFS. Got consistent 50mbps. Where did you write the file to and from? You said your Pi is a NFS client so I assume you wrote a file to a server and read it back from there. > According to iperf, I could go as high as 82.2 mbps. Not the fair > gigabit I have on this LAN, but close to theoretical 100mbit limit of > the NIC. iperf does no file I/O so nearly every CPU cylce can be used for the USB transfer. > During the NFS test, two kernel threads were the worst CPU > consumers, kworker/0 and ksoftirqd/0. > During the iperf test, the worst CPU consumers were iperf itself and > ksoftirqd/0. > According to the /proc/interrupts, the top interrupt consumer was > IRQ32, which is: > dwc_otg, dwc_otg_pcd, dwc_otg_hcd:usb1 That is the driver for the USB port, a DesignWare OnTheGo USB controller. The controller is able to drive the USB port as either a host or a client. This chip and the driver are a constant "work in progress" and depending on the kernel version and the firmware your luck with the USB port on the Pi might be better or worse. For example: http://ludovicrousseau.blogspot.de/2014/04/usb-issues-with-raspberry-pi.html So maybe by updating the bootloader and GPU firmware to the latest from https://github.com/raspberrypi/firmware one might be able to improve the situation. Grüße, Sven. -- Sigmentation fault. Core dumped. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/7bn4gvfph...@mids.svenhartge.de
