VERY(!) slow FTP sometimes

[Joel Sherrill]

Arnout Vandecappelle wrote:
> Leon Pollak wrote:
>   
>> Hello, all.
>>
>> I incorporated the RTEMS ftpd to my MPC8247 at 150MHz based board with 100BT FCC
>> controller and made several main tests - everything seems to work fine. I can
>> upload/download files by Linux ftp client, FireFox in Linux and IE in
>> Windows.
>>
>> Now, when I decided to test the speed, I encountered the following VERY
>> strange numbers:
>> 1. IE as a client: in 100% of attempts the speed was about 14-16 KB/s.
>> 2. FireFox(Linux) as a client:
>>       - in 90% of attempts the speed was about 400-460KB/s
>>       - in about 10% - 7-8 KB/s.
>> Even in the "good" FireFox tests (above 400KB/s) the behavior looks also
>> strange a bit: it immediately starts at some number (once at 410KB/s, then at
>> 450KB/s, etc...) and does not change never more.
>>
>> 1. What may be the cause of the VERY low speed cases?
>> 2. Is the "good" speed really good for my case? Can somebody provide numbers
>> from his/her experience?
>>     
>  I think you'll need to collect more information.  Here are some hints:
> * I guess all machines are connected to the same switch?  Try doing a
> similar ftp from IE to the Linux box and see if it behaves similarly.
> * During a slow transfer from the linux box, look at the output of
> ifconfig and netstat -t; check if there are errors or long TCP queues.
> * Try with something different than ftp.  E.g., use the netdemo
> application from network-demos and connect to its echo port (24742).
> You can send a large file to it using netcat: time /bin/nc -q 1 -n -vv
> [IP addr] 24742 < [some large file] > /dev/null
> It reports at the end how many bytes were transferred, from that and the
> time info you can derive speed.  The -q 1 is to force netcat to wait for
> the echo response at the end of the file.
> * In the netdemo application, you can also print network statistics with
> the 's' command on the console.
>   
Other random things to try:

+ Run ttcp -- eliminate the ftpd and filesystem from the equation.
+ Increase mbufs in RTEMS network configuration. 
+ Configure shttpd and fetch the file via httpd.  That keeps the
    filesystem in the equation and eliminates ftpd.
+ Try wget as a "browser"
>  Good luck!
>  Regards,
>  Arnout
>
> --
> Arnout Vandecappelle                     arnout at mind be
> Senior Embedded Software Architect       +32-16-286540
> Mind Embedded Development (an Essensium division)
> GPG fingerprint:  D206 D44B 5155 DF98 550D  3F2A 2213 88AA A1C7 C933
>
> _______________________________________________
> rtems-users mailing list
> rtems-users at rtems.com
> http://rtems.rtems.org/mailman/listinfo/rtems-users
>   


-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at OARcorp.com        On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
   Support Available             (256) 722-9985