We tried turn on the IRQ_Balance and it didn't seem to work it out. Will try with another pair of Gig NIC card with the NAPI function
We are still seeing high soft interrupt occupancy & packet loss when the traffic is above 300Mbps. And below warning message were seen after we shut down the Server Fast_RTC: lost around 75 interrupts on 8192hz Fast_RTC: lost around 75 interrupts on 8192hz Fast_RTC: lost around 75 interrupts on 8192hz Thanks Stephen Thanks Stephen -----Original Message----- From: Ernst van der Plas [mailto:[EMAIL PROTECTED] Sent: 2007年12月4日 19:26 To: Stephen Wang Cc: [EMAIL PROTECTED]; nistnet@antd.nist.gov Subject: Re: [nistnet] [Help] - NISTNET occupy lots of soft interrupts while traffic up Stephen I have no experience with irq balance. I do remember to have seen though, that with a certain level of interrupt the irq's are divided between the 2 cores of a dual core machine. Which again intruduces a greater variance in inter packet delay. I dont know about the engineering limit of NistNet. Ernst [EMAIL PROTECTED] wrote: > Hi Ernst > > Thanks for your prompt reply. I will try once I get a better > understanding of what NAPI is? And is it useful to look into IRQ balance > as well? > > Another question, what is the engineering limit for NISTNet traffic? > > According to the calibration result on NISTnet webpage, it could be up > to 1Gbps. However, my testing results shows that the maximum supported is > > 80,000 packet/s×512byte×8=320Mbps. > > Thanks > > Stephen > > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: 2007年12月4日 16:11 > To: Stephen Wang > Cc: nistnet@antd.nist.gov > Subject: Re: [nistnet] [Help] - NISTNET occupy lots of soft interrupts > while traffic up > > Stephen, > > It could be that if youre system receives an interrupt for every packet > > that is received and send. It is bound to choke at some point. You > > could try to enable NAPI in the kernel. Which switches from interrupts > > to polling when a certain level of interrupts is met. However you will > > get some clustering of the send packets. i.e. the send inter packet > > delay will vary somewhat more than with the interrupts. > > Ernst > >> > >> > >> Dear NISTNET Supporter > >> > >> > >> > >> I have been experiencing problems when testing NISTNET with Smartbit > >> 6000C. Could you please help? Thanks in advance. > >> > >> > >> > >> > >> > >> Test Platform > >> > >> _____________<_____________ > >> | eth1 | eth0 > >> NISTNet server SmartBit 6000B > >> | eth2 | eth3 > >> ------------------------>---------------------- > >> > >> > >> > >> Smartbit(6000B) : 2¡Á1000M SX fiber > >> > >> NISTNET Server: 2 x 3.2GHz CPU (Dual Core), 4G RAM, 2 ¡ÁHP NC373F PCI > >> Express Gigabits > >> > >> Red Hat Linux Kernel: 2.6.13 > >> > >> NISTNET: 2.0.12c > >> > >> > >> > >> > >> > >> IP£º > >> eth0 = 10.100.10.14/24 > >> eth1 = 10.100.10.15/24 > >> eth2 = 10.100.20.15/24 > >> eth3 = 10.100.20.14/24 > >> > >> > >> > >> > >> > >> Test Strategy > >> > >> Smartbit sends IP packet from eth0 to eth3; NISTNET server starts the IP > >> Forwarding; Meanwhile NISTNET injects delay. > >> > >> > >> > >> 1. Don¡¯t start NISTNET, drive through 800Mbps traffic from eth0, on > >> NISTNET server, with ¡°top¡± command see that ksoftirqd/0 process takes up > >> almost 99% CPU, about 0.01 % packet loss are seen on > >> > >> eth3, > >> > >> 2. Start NISTNET, inject delay,jitter cnistnet ¨Ca 10.100.10.14 > >> 10.100.20.14 add new ¨Cdelay 15 5 > >> > >> The traffic exceeds 350Mbps, with ¡°top¡± command we see that SI (soft > >> interrupt) of CPU increasing dramatically. And even the server will go > >> down. > >> > >> > >> > >> > >> > >> Enquiry > >> > >> Why NISTNET will occupy so many SI resources of CPU when traffic is up? > >> Any ideas to improve? > >> > >> > >> > >> > >> > >> Thanks > >> > >> Stephen > >> > >> > >> > >> > >> > >> > >> > >> > >> -- > >> This message has been scanned for viruses and is believed to be clean > >> > >> _______________________________________________ > >> nistnet mailing list > >> nistnet@antd.nist.gov > >> http://www-x.antd.nist.gov/mailman/listinfo/nistnet > >> > > > > -- > > This message has been scanned for viruses and is believed to be clean > > > -- > This message has been scanned for viruses and is believed to be clean. -- This message has been scanned for viruses and is believed to be clean
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