[Ilugc] internet speed issues with ubuntu
- From: girishvenkatachalam@xxxxxxxxx (Girish Venkatachalam)
- Date: Tue Jan 9 18:45:36 2007
On Tue, Jan 09, 2007 at 11:02:22AM +0100, Binand Sethumadhavan wrote:
On 08/01/07, Mano <manokaran@xxxxxxxxx> wrote:
Its 418 ms now. Do not know what it was yesterday :-)
Well, with that RTT, the theoretic throughput you should see is:
throughput = buffer size / RTT
= (87380 / 1024) / (418 / 1000) = 204 KB/sec
So what Prozilla got is fine. It had to use multiple threads to fill
up your bandwidth, of course. I imagine Prozilla sets the buffer size
to 64 KB.
Of course, a single thread cannot fill up your pipe (since you are
quite far away from the server). In practice, a single-threaded
downloader's performance will go down as you go further and further
away from the server (as measured by RTT). The only way to counter
this is to increase the number of threads (until your pipe fills up,
of course). I think firefox has a few very aggressive download
managers that can tune your TCP parameters to get similar speeds as
prozilla.
Oops! This reasoning is absolute rubbish.
TCP gives more throughput if you use more connections but this has nothing
whatsoever to do with threads. Look at the implementation of axel download
manager to figure out how it uses multiple TCP connections in a single thread
to achieve high throughput.
But usually the UNIX world shies away from this approach of opening multiple
connections since it is against the philosophy of being a "good citizen."
Anyway TCP has no upper limit on how much throughput a single connection can
give. It does have problems with LFNs and wireless networks but definitely
those things do not apply here.
So here without resorting to any complications one should obtain the best
throughput with a single TCP connection in a single threaded single process.
Please check your facts. :)
regards,
Girish
Other related posts:
