lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sun, 06 Apr 2008 15:27:57 -0500
From:	Wenji Wu <>
To:	Sangtae Ha <>
Cc:	Ilpo Järvinen <>,
	John Heffner <>,
	Netdev <>
Subject: Re: A Linux TCP SACK Question

> Can you run the attached script and run your testing again?
> I think it might be the problem of your dual cores balance the
> interrupts on your testing NIC.
> As we do a lot of things with SACK, cache misses and etc. might affect
> your performance.
> In default setting, I disabled tcp segment offload and did a smp
> affinity setting to CPU 0.
> Please change "INF" to your interface name and let us know the results.

I bound the network interrupts and iperf both the CPU0, and CPU0 will be ilde most of the time. The results are still the same.

At this throughput level, the SACK processing won't take much CPU. 

It is not the interrupt/cpu affinity that cause the difference. 

I am beleving that it is the ACK reordering that cuase the confusion in the sender, which lead the sender uncecessarily to reduce CWND or REORDERING_THRESHOLD.

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists