TUX ftp server performance

[Ravi Parimi <parimi@ece.arizona.edu>]

Hi,

	Have a few basic questions on TUX as an FTP server. I configured
tux as an FTP server after reading the docs at
http://people.redhat.com/mingo/TUX-patches/2.1-docs/index.html

Anonymous logins work fine. I am comparing the performance of Tux's ftp
server with a user-space ftp server like proftpd. Here are a few results
that I gathered :

1) TUX as an FTP server

 (Two separate networks)                        (Same Lan - 100MBps)
File size  Time taken (seconds)           File size	Time taken(seconds)
1K		0.00169			     1K			0.000286
2K		0.00241			     2K			0.000386
4K		0.00399			     4K			0.00056
8K		0.00817			     8K			0.00101
16K		0.0147			     16K		0.00201
32K		0.0297			     32K		0.00349
64K		0.0564			     64K		0.00648
128K		0.113			     128K   		0.012
256K		0.235			     256K		0.0232
512K		0.448			     512K		0.052
1024K		0.893			     1024K		0.0953


2) Proftpd as FTP server

 (Two separate networks)                        (Same Lan - 100MBps)
File size  Time taken (seconds)           File size	Time taken(seconds)
1K		0.0013			     1K			0.000315
2K		0.0021			     2K			0.000401
4K		0.0041			     4K			0.000606
8K		0.0075 			     8K			0.000975
16K		0.015			     16K		0.00169
32K		0.029			     32K		0.00309
64K		0.056			     64K		0.00585
128K		0.11			     128K		0.017
256K		0.22			     256K		0.0225
512K		0.45			     512K		0.0449
1024K		0.89			     1024K		0.0891

As you can observe, the performance of proftpd server seems to be better
in all cases for file sizes greater than 4K. I havent used fancy
methods to measure time - just noted the time from the output of the
default ftp client on redhat.

Can someone give me some hints/reasons on why proftpd seems to serve
better? The first page of the TUX manual says "With a capable network
card, TUX enables direct scatter-gather DMA from the page cache directly
to the network, thus avoiding data copies". I am not sure if this applies
just to the web server, or to both the web and ftp servers. Should I
supply specific configuration switches to the ftp server to enahance its
performance? Or am I missing something ? I agree that other factors such
as network traffic, server load etc. might affect results, but shouldnt
TUX be at least marginially better than proftpd ?

Thanks,
--ravi