Re: XTP for 2.6.25

From: Shigeo N
Date: Wed May 07 2008 - 00:32:24 EST


I tested again on Linux 2.6.25 with TCP reordering patch.
Of course, TCP performance was improved.

Here is the result.

case2-2) random delay (with TCP reordering patch)

In this case, add a fixed amount of delay + 10% random delay by command,
"tc change dev eth0 root netem delay 100ms 10ms 25%".

fixed delay UDP/TCP/XTP throghput
---------------------------------------
10ms 88/85/92 Mbps
30ms 88/67/91 Mbps
50ms 88/58/89 Mbps
70ms 88/43/80 Mbps
100ms 88/26/66 Mbps

case2) random delay (without TCP reordering patch)

In this case, add a fixed amount of delay + 10% random delay by command,
"tc change dev eth0 root netem delay 100ms 10ms 25%".

fixed delay UDP/TCP/XTP throghput
---------------------------------------
10ms 88/80/92 Mbps
30ms 88/51/91 Mbps
50ms 88/41/89 Mbps
70ms 88/28/80 Mbps
100ms 88/19/66 Mbps

case1) fixed delay

In this case, just adds a fixed amount of delay to all packets going out by
command, "tc qdisc add dev eth0 root netem delay 100ms".

fixed delay UDP/TCP/XTP throghput
---------------------------------------
10ms 88/85/92 Mbps
30ms 88/70/91 Mbps
50ms 88/63/89 Mbps
70ms 88/52/84 Mbps
100ms 88/36/70 Mbps

Thanks,

On Fri, Apr 25, 2008 at 5:23 PM, Ilpo JÃrvinen
<ilpo.jarvinen@xxxxxxxxxxx> wrote:
> On Fri, 25 Apr 2008, Shigeo N wrote:
>
>> case2) random delay
>>
>> In this case, add a fixed amount of delay + 10% random delay by
>> command, "tc change dev eth0 root netem delay 100ms 10ms 25%".
>>
>> Here is the result.
>>
>> fixed delay UDP/TCP/XTP throghput
>> ---------------------------------------
>> 10ms 88/80/92 Mbps
>> 30ms 88/51/91 Mbps
>> 50ms 88/41/89 Mbps
>> 70ms 88/28/80 Mbps
>> 100ms 88/19/66 Mbps
>>
>> TCP's perfomance looks very poor when delay is long and variable.
>
> Where these results with 2.6.25 as well? ...John Heffner just couple of
> days ago fixed reordering related problem in TCP (in case that netem
> parametrization causes reordering), the fix is not even in 2.6.24.y, I
> think...
>
> --
> i.
>
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