Subject: Re: Network throughput and upgrading kernel questions
To: Blaz Antonic <email@example.com>
From: Brian Chase <firstname.lastname@example.org>
Date: 05/02/2003 08:59:09
On Fri, 2 May 2003, Blaz Antonic wrote:
> I was downloading some stuff with my VS3100/m38 yesterday and i noticed
> i get different throughput when using Lynx (preferred because i can
> browse FTP sites) and wget:
> When downloading something from external (outside local network) FTP i
> got throughput of ~50 KB/s with Lynx and ~60 KB/s with wget;
> When downloading something from local FTP (another box on same network
> segment) i got throughput of 150 KB/s with Lynx and 220 KB/s with wget.
> I could imagine speed degradation in latter case being caused by the
> slow CPU (Lynx doing it less efficiently, with more instructions to
> execute so CPU gets clogged up) but that doesn't explain the difference
> between 50 and 60 KB/s where CPU should be able to handle it fine (it
> can handle 150 KB/s with Lynx as proven by testing). Any ideas as to
> what might be causing the slowdown ? What's ironic is that wget appears
> to be doing more stuff while downloading (cosmetic updates to screen to
> reflect progress).
> I'm also curious as to what kind of throughputs do you people get with
> Lynx and wget on VS3100/m38/m48 kind of CPU and on faster machines (like
> VS4k m96). Perhaps i should also mention that there was next to no
> network rtraffic going on while i was testing (it would slow traffic
> down further because of collisions otherwise).
On my 16MB MicroVAX 3100/20e (slightly slower than a VS3100/m38) and
1.6, I see around 230KB/s with local FTP transfers using the NetBSD ftp
client. With lynx I get around 160KB/s. That seems to be similar to
what you're seeing. The slightly better performance for my slower CPU
is possibly due my download drive being a 4GB SCSI-2 Seagate ST15150N.
My assessment would be that Lynx just isn't a very efficient FTP
client. I'd tend to suggest using the NetBSD provided ftp client as
demonstrating what is close to being the fastest possible speed for
ftping with your particular hardware configuration.
Another thing to consider apart from CPU speed and disk speed is also
how much RAM you have. If you're running on an 8MB or less system, I'd
expect that will start to cause general slowdowns. I'd also note that
lynx seems to be doing some sort of curses/ncurses based updates as
it's transferring the file. I think your best bet for figuring out
why lynx is slower will be to look at how the FTP download portion of
it is coded. With your wget test, you've already narrowed the problem
down to something that's lynx specific.