Re: [hybi] Multiplexing: Pre-AddChannelResponse quota

[Takeshi Yoshino <[e-mail]>]

On Thu, Jun 14, 2012 at 6:58 PM, Arman Djusupov <[e-mail]> wrote:

> -- send quota for X is set to (PQ_i) - (total pre-handshake data sent) +
> (initial send quota assigned by the AddChannelResponse)****
>
> ** **
>
> The quota header in AddChannelResponse is not needed, the server can
> supplement the client quota using normal flow control frames. This would
> simplify it a bit. If the server needs to grant additional quota right
> after the AddChannelResponse, it can send an FC block in the same frame
> with the AddChannelResponse. The FC block format is more efficient than the
> literal format of the AddChannelResponse header.
>

OK


> ****
>
> - When received, say, PreHandshakeQuota block, split it up and add to
> slots so that PQ_k are leveled (older ones first) among all slots
>
> ** **
>
> Why to split up the quota? This leave room for strange cases when the
> quota is not divisible by the number of channels. Why not simply set or add
> a value to each already allocated slot?
>

I tried to make it able to gradually decrease PQ_i for new slots when the
server is overloaded.

If PreHandshakeQuota adds the same value to each allocated slot, PQ_i for a
new channel needs to be initialized to the same value as the other slots'
on NewChannelQuota. Otherwise, PQ_i values are in-balanced between the new
one and the others. Then, ... there's no way to  decrease PQ_i.

We may add a new channel with slightly smaller PQ_i to allow for
suppression. This works, but one of its cons is that we cannot level PQ_i
of allocated slots even when the server gets less loaded again because the
PreHandshakeQuota keeps high slots high and low slots low.