Re: [Lksctp-developers] Readout cwnd and ssthresh value

[Wei Y. <yj...@cn...>]

Vlad Yasevich wrote:
> Wei Yongjun wrote:
>   
>> Frank Schuster wrote:
>>     
>>> Hi Vlad,
>>>
>>> ok, I understand this.
>>>
>>> I want to use netperf with some different tests but as I see, Linux can't help for this problem.
>>> I will ask the netperf-developer,  if I can build in the cwnd option in an easy way or it is to hard.
>>>
>>> But Linux has no tool or something like this - to show the sctp slow start?
>>>   
>>>       
>> I think we need something like tcp_probe kernel module to
>> show those informations we need. create sctp_probe kernel
>> module, insert a kprobe trace point to sctp_sf_do_prm_send()
>> or the other place to show the cwnd, thresh etc. of an asoc.
>> If it is worth, I will continue to this.
>>
>> some other ideas?
>>
>>     
>
> Probably better, from the application perspective, is to do something like
> TCP_INFO socket option (at least for 1-1 sockets).  I think SCTP_STATUS was
> supposed to be something like this, but it's rather limiting.
>
> Another item that I've wanted to do is a Netlink interface into SCTP to get
> all the association statistics ala tcp_diag.  This is the most extensible
> interface as you can attributes to it in a backward-compatible manner.
>   

This is a good idea, but this need both change to kernel and the
iproute2(?) tool. Maybe we need to wait a long time before we can
use this. one year ago, we've requested to do this from customer,
but after then they give up.

This may also need some changes to the diag interface.

Does anyone doing this now?

> The kprobe isn't the simplest to use from the application point of view.
>
> -vlad
>
>
>