Re: TCP transmit performance regression

Ming Lei
2012-07-05T08:42:40Z

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On Thu, Jul 5, 2012 at 4:33 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Thu, 2012-07-05 at 16:27 +0800, Ming Lei wrote:
>
>> After some investigation, the problem is caused by enabling
>> DEBUG_SLAB, so it is not a regression.
>>
>
> Strange, unless your machine is a _very_ slow one maybe ?

It is a beagle-xm board, and its cpu is ARMv7, 1GHz.

>
>>
>> Looks no improvement. I still don't know why the window size becomes so
>> small even in good situation(disabling DEBUG_SLAB), and the small
>> window size will cause almost every tcp data packet acked.
>
> You are probably missing the fact that window scaling is enabled.
>
> If you dont post a pcap, I am afraid we cant really help.

See attachment for the pcap trace.

Thanks,
--
Ming Lei

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