From mboxrd@z Thu Jan 1 00:00:00 1970 From: H M Thalib Subject: Re: 100Mbit ethernet performance on embedded devices Date: Thu, 27 Aug 2009 21:08:25 +0530 Message-ID: <4A96A871.3090002@gmail.com> References: <20090819145057.GA25400@sig21.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from :user-agent:mime-version:to:cc:subject:references:in-reply-to :content-type:content-transfer-encoding; bh=814/9TsLlGuFId9auiFLTwuOCLqcR0PSsp8LMv84mdA=; b=rfpsX7m0vi3VKScANdTNM0S/JWE1ELRDTmM4xp0l9MtavSsWCPdeoYtyJJeCd9paUw j4Eclnkjn2h5XDvbxQVpfbyYW+3HsyGBRTGqUBURak0dp04foCsfCfGEkLZEN99yay7Y taaiJNHcDk7PyLGHxvuWsOKB7cOJ2VwavXB/k= In-Reply-To: <20090819145057.GA25400@sig21.net> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Johannes Stezenbach Cc: linux-embedded@vger.kernel.org, netdev@vger.kernel.org Hi, 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: > Did you used Iperf it is not the correct tool to find the performance of ethernet. use tools like Smartbits or IXIA they are special hardware to measure the performance . They will give you better results > 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) Did you stopped unwanted process in both PC as well as processor, make sure PC has a bottle neck. Does it gives a through put of at least 95MBps. Is you system connected directly with crossover cables. > The CPU load during the iperf test is around > 1% user, 44% system, 4% irq, 48% softirq, with 7500 irqs/sec. Did you used vmast -- it is not the correct way to measure the cpu load or do you use top -- it takes lots of you system resource .. this can affect ehternet performance > 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. Thats good. iptable will dramatically affect the performance. remove all the iptables related modules if it is loaded before performing test 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. > not bad. worth upgrading. > 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.) surely you will not find the perf data for small low end processor because they are not made fro that. and also this data is not some thing sharable .they are the benchmark about their product. Industry is interested in high performance processor for network product. beside ethernet they do have lot offloading engines. > 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. probably should be possible optimizing hardware+software but you have to pay for that. > 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. In my experience for your cpu 80% max of ehternet speed should be ok .. don't expect more. > > Did anyone actually manage to get close to 100Mbit/sec > with similar CPU resources? > > > TIA, > Johannes > -- > To unsubscribe from this list: send the line "unsubscribe linux-embedded" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Thanks & Regards, H M Thalib.