Re: [PATCH] tcp_cubic: limit delayed_ack ratio to prevent divide error

TB
2011-05-06T16:15:24Z

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On 11-05-04 04:53 PM, Brandeburg, Jesse wrote:
>
>
> On Wed, 4 May 2011, Stephen Hemminger wrote:
>
>> TCP Cubic keeps a metric that estimates the amount of delayed
>> acknowledgements to use in adjusting the window. If an abnormally
>> large number of packets are acknowledged at once, then the update
>> could wrap and reach zero. This kind of ACK could only
>> happen when there was a large window and huge number of
>> ACK's were lost.
>>
>> This patch limits the value of delayed ack ratio. The choice of 32
>> is just a conservative value since normally it should be range of
>> 1 to 4 packets.
>>
>> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> patch seems fine, but please credit the reporter (lkml@techboom.com) with
> reporting the issue with logs, maybe even with Reported-by: and some kind
> of reference to the panic message or the email thread in the text or
> header?

We're currently testing the patch on 6 production servers

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