netdev - RE: Question on "net: allocate skbs on local node"

lists.openwall.net		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 linux-hardening linux-cve-announce 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]

Message-ID: <1302153412.2701.64.camel@edumazet-laptop>
Date:	Thu, 07 Apr 2011 07:16:52 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Wei Gu <wei.gu@...csson.com>
Cc:	netdev <netdev@...r.kernel.org>,
	Alexander Duyck <alexander.h.duyck@...el.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: RE: Question on "net: allocate skbs on local node"

Le jeudi 07 avril 2011 à 06:58 +0200, Eric Dumazet a écrit :
> Le jeudi 07 avril 2011 à 10:16 +0800, Wei Gu a écrit :
> > Hi Eric,
> > Testing with ixgbe Linux 2.6.38 driver:
> > We have a little better thruput figure with this driver, but it looks
> > not scalling at all, I always stressed one CPU core/24.
> > And when look the perf report for ksoftirqd/24, the most cost function
> > is still "_raw_spin_unlock_irqstore" and the IRQ/s is huge, it's
> > somehow conflicts with desgin of NAPI. On linux 2.6.32 while the CPU
> > was stressed the IRQ will descreased while the NAPI will running much
> > on the polling mode. I don't know why on 2.6.38 the IRQ was keep
> > increasing.
> 
> 
> CC netdev and Intel guys, since they said it should not happen (TM)
> 
> IF you dont use DCA (make sure ioatdma module is not loaded), how comes
> alloc_iova() is called at all ?
> 
> IF you use DCA, how comes its called, since the same CPU serves a given
> interrupt ?
> 
> 

But then, maybe you forgot to cpu affine IRQS ?

High performance routing setup is tricky, since you probably want to
disable many features that are ON by default : Most machines act as a
end host.



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html