Re: collapsed_forwarding and ICP

Thanks. I may have a look into putting those knobs in...

On 06/02/2009, at 11:18 AM, Henrik Nordstrom wrote:

> fre 2009-02-06 klockan 10:07 +1100 skrev Mark Nottingham:
>> If I have a peer and it has collapsed_forwarding on, at what point
>> will it return an ICP_HIT to me? E.g.,
>>
>> 1) As soon as there's an outstanding (therefore collapsed) request
>> for
>> it?
>> 2) As soon as there's a cacheable response in-flight for it?
>> 3) Only when the entire response is in-cache?
>>
>> My reading of the code is that it's #1. Do I have this right?
>
> Probably.
>
>> If that's the case:
>> - On the plus side, this helps collapse requests across peers.
>
> Yes.
>
>> - On the down side, it seems like there's the potential for requests
>> to go to peers, only to find that the response is uncacheable.
>
> Yes, and the slower the origin is to respond the more you'll see of
> this.
>
> Should be trivial to add a tuning knob to ICP for this. The "not yet
> known if they may be cached" objects have a special KEY_EARLY_PUBLIC
> flag set. See icpCheckUdpHit() for a suitable spot. htcpCheckHit would
> also need the same.
>
> Regards
> Henrik
>

--
Mark Nottingham       mnot_at_yahoo-inc.com