Reco <recovery...@gmail.com> wrote: > On Fri, Jun 19, 2015 at 02:47:20PM +0200, Petter Adsen wrote: >> On Fri, 19 Jun 2015 14:09:45 +0200 >> basti <black.flederm...@arcor.de> wrote: >>> On 19.06.2015 14:03, Sven Hartge wrote: >>>> basti <black.flederm...@arcor.de> wrote:
>>>>> iotop show me a read speed around 3 MB/s, there is a Class 10 UHS >>>>> card (10-15 MB/s read, 9-5 MB/s write I guess). >>>> More than 3MByte/s is not really achievable with a Pi-1, because >>>> the CPU is very weak and the Ethernet-Chip is attached via USB. >>>> >>>> Under the best conditions you may be able to transfer up to >>>> 45MBit/s, but a maximum transfer rate of about 35MBit/s is normal. >>> The Problem is not the speed of 3 MB/s it's the load of 12 and more. >> >> The load is so high because USB is very CPU-intensive. If you were to >> use the on-board Ethernet, you would not see such a high load. > What? Are you serious? I have this Nokia N900 lying behind me which is > connected by IP-via-USB (aka usbnet aka g_ether) and with the order of > magnitude slower ARM CPU it reliably shows 40mbps with no noticeable > load. Maybe the USB hardware implementation is better in the N900? The one in the Pi is quite bad and finicky. 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. If the source or destination of the transmitted data is on an USB medium it gets even worse because all USB ports share the same root port on the SoC. Besides: I always found the load on Linux NFS servers to be higher than on a Samba-Server with equal throughput. I guess the calculation of the load is different for the NFS kernel server process than for userland fileservices. 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/4bn4bukph...@mids.svenhartge.de
