Messages in this thread | | | Date | Thu, 24 Apr 2008 22:06:11 +0900 | From | "Shigeo N" <> | Subject | Re: XTP for 2.6.25 |
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Now I have connected 2 hosts directly, and evaluate the each throughput. Then all the results of UDP, TCP and XTP are the same and 94Mbps. (My netwrok is 100Base/TX).
In this case round-trip time between 2 hosts is less than 0.1ms because they are directly connected. But my previouse case, round-trip time between 2 hosts are 4ms. (I use IPSEC between the security gateways to increase delay). I think that's the reason TCP throughput is slow. If ACK packets are delayed, sending window cannot slide and sending packets cannot be fully bursted.
If I changes wmem size through /proc/sys/net/ipv4/tcp_wmem, TCP's throughput may improve, but congestion control becomes more difficult for TCP.
That is TCP's disadvantage to XTP.
Best Shigeo
On 4/24/08, Andi Kleen <andi@firstfloor.org> wrote: > "Shigeo N" <shigeonx@gmail.com> writes: > > > > I tested in the network where UDP throughput is 29Mbps, then TCP > > throughput was 13Mbps, but XTP's reached to 25Mbps. > > One interesting question is why TCP was so much slower than UDP > on your test. It shouldn't be on a fair test setup. > > Please post details. Was the network losing packets? > > New protocols might be interesting, but even more interesting is to > fix any (real) problems in existing protocols. > > -Andi >
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