Re: [PATCH net-next] sctp: support per-association stats via a new SCTP_GET_ASSOC_STATS call

[Vlad Yasevich <vyasevich@gmail.com>]

On 10/29/2012 12:38 PM, Neil Horman wrote:
> On Sat, Oct 27, 2012 at 11:48:33AM -0400, Vlad Yasevich wrote:
>>
>>
>>
>>
>> On Oct 27, 2012, at 7:35 AM, Michele Baldessari <michele@acksyn.org> wrote:
>>
>>> Hi Neil & Vlad,
>>>
>>> On Fri, Oct 26, 2012 at 10:37:04AM -0400, Neil Horman wrote:
>>>> We already have files in /proc/net/sctp to count snmp system-wide totals,
>>>> per-endpoint totals, and per association totals.  Why do these stats differently
>>>> instead of just adding them the per-association file?  I get that solaris does
>>>> this, but its not codified in any of the RFC's or other standards.  I would
>>>> really rather see something like this go into the interfaces we have, rather
>>>> than creating a new one.
>>>>
>>>> I also am a bit confused regarding the stats themselves.  Most are fairly clear,
>>>> but some seem lacking (you count most things sent and received, but only count
>>>> received gap acks).  Others seems vague and or confusing (when counting
>>>> retransmitted chunks and packets, how do you count a packet that has both new
>>>> and retransmitted chunks)?  And the max observed rto stat is just odd.  Each
>>>> transport has an rto value, not each association, and you cal already see the
>>>> individual transport rto values in /proc/net/sctp/remaddr.
>>>
>>> thanks a lot for your time reviewing this. I will try to address all
>>> your comments in a second version of the patch. One thing I am not too
>>> sure though: do you prefer me extending /proc/net/sctp/* or implement a
>>> new call.
>>>
>>> I ask because from a previous private communication with Vlad the new
>>> socket option seemed to be the preferred approach.
>>> I am fine either way just let me know ;)
>>
>>
>> socket option is preferable as /proc doesn't scale very well as number of associations grows.
>>
>> -Vlad
>>
> I completely agree with that notion, but at the same time, the socket option is
> limited in that these stats will only be accessible to the process that owns the
> socket.  I imagine that someone will eventually ask for these stats to be made
> available to utilities outside of the owning socket.
> Neil

I am sure they will, but I know of several applications that as part of 
debugging information periodically fetch the stats.  For them it is much 
simpler to use socket options.

-vlad

>
>>>
>>> cheers,
>>> --
>>> Michele Baldessari            <michele@acksyn.org>
>>> C2A5 9DA3 9961 4FFB E01B  D0BC DDD4 DCCB 7515 5C6D
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