TCP DELAY

TCP DELAY

[Latha B lingaiah]

Hi,

While transfering a 42MB file, there seem to be a TCP
delay between the kernels 2.4.7 and 2.4.18.

Here are some data :-

In 2.4.7 kernel :

43843584B in 4.486s = 9.77342e+06B/s = 9544.36KB/s =
9.32066MB/s

In 2.4.18 kernel :
 43843584B in 3.711s = 1.18145e+07B/s = 11537.6KB/s =
11.2672MB/s

I am looking at the reason behind the delay in 2.4.7
kernel. Any comments on this?



PS: Please CC me with reply, as i am not subscribed to
the list.

thanks,
latha

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Re: TCP DELAY

[bert hubert]

On Sun, Oct 20, 2002 at 11:56:00PM -0700, Latha B lingaiah wrote:
> Hi,
> 
> While transfering a 42MB file, there seem to be a TCP
> delay between the kernels 2.4.7 and 2.4.18.

Don't do such short measurements, 4.5 seconds is no way to do statistics.
TCP/IP does not start out at full speed but takes some time to find the
right speed.

Regards,

bert

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Re: TCP DELAY

[Rogier Wolff]

On Mon, Oct 21, 2002 at 08:58:39AM +0200, bert hubert wrote:
> On Sun, Oct 20, 2002 at 11:56:00PM -0700, Latha B lingaiah wrote:
> > Hi,
> > 
> > While transfering a 42MB file, there seem to be a TCP
> > delay between the kernels 2.4.7 and 2.4.18.
> 
> Don't do such short measurements, 4.5 seconds is no way to do statistics.
> TCP/IP does not start out at full speed but takes some time to find the
> right speed.

If all you do is repeatedly transfer small files of only 42Mb, the
difference of 18% between 3.7 and 4.4 seconds is quite measureable. 

But you should measure the difference more than once, but I suspect
that this was indeed done.....

			Roger. 

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