PHWinfo - Afficher un message - Gigabit Ethernet, and Linux -- first observations

12/09/2007, 15h32

On Tue, 11 Sep 2007 23:02:37 -0500, Ignoramus26973 wrote:

> I installed a gigabit network switch and a gigabit enabled laptop wifi
> adapter (with gigabit, obviously, available on ethernet ports only) in
> my house.
>
> Two computers in my home are connected to the switch and one (laptop)
> to the wifi adaptor.
>
> The highest possible speed of a gigabit connection is about 111
> megabytes per second.
>
> Naturally, I did some tests with a noncompressible 1 gigabyte long
> file (fragment of some gzipped file exactly one GB long).
>
> My first test was to scp files from one computer on the switch to
> another. Here, I was disappointed as the highest speed was only 22
> megabytes per second one way and 46 another way. About 20 and 40
> percent of maximum.
>
> Then I tried using HTTP to transfer the same file (both computers are
> webservers). To my huge surprise, it made a world of difference and
> the transfer speed was 111 or so megabytes per second.
>
> So, now I have a dilemma, I have a fast pipe, but scp is not fast
> enough (given my CPU) to encrypt/decrypt so much data.
>
> I tried something else, which is doing wc -l on a NFS mounted drive
> (same two computers). It was UNBELIEVABLY slow and the load average on
> the NFS server shot WAY up. Transferring a 336 MB file took 157
> seconds, or about e megabytes per second (vs 111 mbps that I achieved
> with HTTP).
>
> So, the conclusion is, HTTP is fast (no wonder), SSH is "medium",
> and NFS is "slow, very bad".
>
> The connection to laptop is a disappointment in its own right, since
> even with all-ethernet connection, I get about 3 megabytes per
> second. I think that I need to pull a new wire in the wall.
>
> So, the short of it is that there is much work to be done.
>
> i

you didn't mention Jumbo Frames.

IF ( BIG IF ) your Gigabit hardware supports 9K MTUs, you can get
a big boost if you set your MTU to 9000 on your nics.

I'll post some numbers from my setup in the next couple of days.

jack

--
D.A.M. - Mothers Against Dyslexia

see http://www.jacksnodgrass.com for my contact info.

jack - Grapevine/Richardson

12/09/2007, 15h32	#5
Jack Snodgrass Messages: n/a Hébergeur:	Re: Gigabit Ethernet, and Linux -- first observations On Tue, 11 Sep 2007 23:02:37 -0500, Ignoramus26973 wrote: > I installed a gigabit network switch and a gigabit enabled laptop wifi > adapter (with gigabit, obviously, available on ethernet ports only) in > my house. > > Two computers in my home are connected to the switch and one (laptop) > to the wifi adaptor. > > The highest possible speed of a gigabit connection is about 111 > megabytes per second. > > Naturally, I did some tests with a noncompressible 1 gigabyte long > file (fragment of some gzipped file exactly one GB long). > > My first test was to scp files from one computer on the switch to > another. Here, I was disappointed as the highest speed was only 22 > megabytes per second one way and 46 another way. About 20 and 40 > percent of maximum. > > Then I tried using HTTP to transfer the same file (both computers are > webservers). To my huge surprise, it made a world of difference and > the transfer speed was 111 or so megabytes per second. > > So, now I have a dilemma, I have a fast pipe, but scp is not fast > enough (given my CPU) to encrypt/decrypt so much data. > > I tried something else, which is doing wc -l on a NFS mounted drive > (same two computers). It was UNBELIEVABLY slow and the load average on > the NFS server shot WAY up. Transferring a 336 MB file took 157 > seconds, or about e megabytes per second (vs 111 mbps that I achieved > with HTTP). > > So, the conclusion is, HTTP is fast (no wonder), SSH is "medium", > and NFS is "slow, very bad". > > The connection to laptop is a disappointment in its own right, since > even with all-ethernet connection, I get about 3 megabytes per > second. I think that I need to pull a new wire in the wall. > > So, the short of it is that there is much work to be done. > > i you didn't mention Jumbo Frames. IF ( BIG IF ) your Gigabit hardware supports 9K MTUs, you can get a big boost if you set your MTU to 9000 on your nics. I'll post some numbers from my setup in the next couple of days. jack -- D.A.M. - Mothers Against Dyslexia see http://www.jacksnodgrass.com for my contact info. jack - Grapevine/Richardson