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TSecr != 0 check in inet_lro.c

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From: Octavian Purdila
Subject: TSecr != 0 check in inet_lro.c
Date: Monday, August 24, 2009 - 2:54 pm

Hi,

We are seeing a performance issue with TSO/LRO which we tracked down to the 
TSecr !=0 check in lro_tcp_ip_check.

It happens when the LRO side's TSval wraps around and gets to 0. That triggers 
the TSO side to send packets with TSecr set to 0, which means that such 
packets won't be aggregated - and that will put a lot of burden on the stack 
which will result in lots of drops.

I'm failing to understand the purpose of this check. Any hints? :)

Thanks,
tavi
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Messages in current thread:
TSecr != 0 check in inet_lro.c, Octavian Purdila, (Mon Aug 24, 2:54 pm)
Re: TSecr != 0 check in inet_lro.c, Eric Dumazet, (Mon Aug 24, 10:42 pm)
Re: TSecr != 0 check in inet_lro.c, Octavian Purdila, (Tue Aug 25, 4:50 am)
Re: TSecr != 0 check in inet_lro.c, David Miller, (Tue Sep 1, 3:46 pm)