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SubjectRe: TSO and IPoIB performance degradation
On Mon, Mar 20, 2006 at 02:04:07PM +0200, Michael S. Tsirkin wrote:
> does not stretch ACKs anymore. RFC 2581 does mention that it might be OK to
> stretch ACKs "after careful consideration", and we are seeing that it helps
> IP over InfiniBand, so recent Linux kernels perform worse in that respect.
> And since there does not seem to be a way to figure it out automagically when
> doing this is a good idea, I proposed adding some kind of knob that will let the
> user apply the consideration for us.

Wouldn't it make sense to strech the ACK when the previous ACK is still in
the TX queue of the device? I know that sort of behaviour was always an
issue on modem links where you don't want to send out redundant ACKs.

"Time is of no importance, Mr. President, only life is important."
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