uftp execution time

[Daven McCalla]

I have an application that needs to send files to 1-10 clients. The file sizes can vary from a few bytes to 80MB.

When I send a small file:
uftp -I wlan1 -b 2100 -Q 34 -H 0xC0A8045A,0xC0A80443 /mnt/sram/printbuf1

uftp reports impressive completion times:

Transfer status:
Host: 0xC0A8045A Status: Completed time: 0.041 seconds
Host: 0xC0A80443 Status: Completed time: 0.044 seconds
Total elapsed time: 0.044 seconds

However, when I measure the total execution time in the program that calls uftp it reports 351ms:

struct timeval start;
gettimeofday(&start, NULL);
system("uftp -I wlan1 -b 2100 -Q 34 -H 0xC0A8045A,0xC0A80443 /mnt/sram/printbuf1");
struct timeval now;
gettimeofday(&now, NULL);
unsigned long ms = (((now.tv_sec - start.tv_sec) * 1000000) + (now.tv_usec - start.tv_usec))/1000;
printf("uftp time = %d ms\n", ms);

There appears to be around 300ms overhead for a 50ms file transfer. Are there additional command line options that will help reduce the total execution time of uftp?

Regards,
Daven

[Dennis Bush]

Daven,

The given elapsed time is for the main transfer phase of the session when actual data packets are being sent. It does not include the overhead of initiating the session.

One thing you could do is set an initial estimate of the round trip time in seconds using the -r option. It defaults to 0.5, but you can set it as low as 0.001. That can shorten the announcement phase, but don't set it too low otherwise small delays could result in the session being dropped.

Regards,
Dennis