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: <1250694317.2874.4.camel@achroite>
Date:	Wed, 19 Aug 2009 16:05:17 +0100
From:	Ben Hutchings <bhutchings@...arflare.com>
To:	Johannes Stezenbach <js@...21.net>
Cc:	linux-embedded@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: 100Mbit ethernet performance on embedded devices

On Wed, 2009-08-19 at 16:50 +0200, Johannes Stezenbach wrote:
> Hi,
> 
> a while ago I was working on a SoC with 200MHz ARM926EJ-S CPU
> and integrated 100Mbit ethernet core, connected on internal
> (fast) memory bus, with DMA.  With iperf I measured:
> 
>   TCP RX ~70Mbit/sec  (iperf -s on SoC, iperf -c on destop PC)
>   TCP TX ~56Mbit/sec  (iperf -s on destop PC, iperf -c o SoC)
> 
> The CPU load during the iperf test is around
> 1% user, 44% system, 4% irq, 48% softirq, with 7500 irqs/sec.
> 
> The kernel used in these measurements does not have iptables
> support, I think packet filtering will slow it down noticably,
> but I didn't actually try.  The ethernet driver uses NAPI,
> but it doesn't seem to be a win judging from the irq/sec number.
> The kernel was an ancient 2.6.20.

Which driver is this?  Is it possible that it does not use NAPI
correctly?

> I tried hard, but I couldn't find any performance figures for
> comparison.  (All performance figures I found refer to 1Gbit
> or 10Gbit server type systems.)
> 
> What I'm interested in are some numbers for similar hardware,
> to find out if my hardware and/or ethernet driver can be improved,
> or if the CPU will always be the limiting factor.
> I'd also be interested to know if hardware checksumming
> support would improve throughput noticably in such a system,
> or if it is only useful for 1Gbit and above.

I have no recent experience with this sort of system, but checksum
offload and scatter/gather DMA support should significantly reduce both
CPU and memory bus load.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

--
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

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ