Re: tux as ftp server question

Cool. Thanks. 

And did you use some ftp benchmark to measure the
networking performance in order to compare the wu.ftpd
and tux ftp server? I find dkftpbench and try to use
it, but it seems there is a limitation with dkftpbench
--- it simulates just dialup user with 28.8k/s. 


sincerely,
li

--- Ingo Molnar <[email protected]> wrote:
> 
> wu.ftpd does the following on 'send a file':
> 
>  [if noncached] DMA data into a kernel-space buffer
> [pagecache]
>  copy pagecache data into user-space buffer
>  copy user-space buffer into kernel-space network
> buffer
>  send/DMA kernel-space network buffer over the
> network
> 
> TUX does:
> 
>  [if noncached] DMA data into a kernel-space buffer
> [pagecache]
>  send/DMA pagecache data over the network
> 
> as you can see, in both the cached and noncached
> case wu.ftpd does two
> copies of the data, while TUX does none. Hence the
> 'zero-copy'.
> 
> Now, if a userspace server uses sendfile(), it will
> not copy data. I
> believe vsFTPd might be such a server? I'm not sure.
> wu.ftpd is definitely
> not such a server.
> 
> obviously there are other, perhaps more important
> differences as well,
> such as feature richness [TUX is anonymous
> download-only], security model,
> and the issue of process modell (TUX uses per-CPU
> processes, wu.ftpd and
> vsFTPd uses [multiple] per connection processes),
> and the protocol parsing
> overhead.
> 
> number of users supported is wastly larger in the
> case of TUX/FTP, eg. on
> the ftp.rpmfind.net FTP server there is a 10
> thousand users limit, and we
> did in fact test so many users.
> 
> The best way to find out is to test a particular
> workload over a local
> network.
> 
> 	Ingo
> 
> 
> 
> _______________________________________________
> tux-list mailing list
> [email protected]
> https://listman.redhat.com/mailman/listinfo/tux-list


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