[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] I/O descriptor ring size bottleneck?
> -----Original Message----- > From: Diwaker Gupta [mailto:diwakergupta@xxxxxxxxx] > Sent: 21 March 2005 00:07 > To: Ian Pratt > Cc: xen-devel@xxxxxxxxxxxxxxxxxxxxx; ian.pratt@xxxxxxxxxxxx > Subject: Re: [Xen-devel] I/O descriptor ring size bottleneck? > > > BTW, I'd actually be very suspicious of dummynet's ability > to operate at > > 500Mb/s. It's possible that the reduced bandwidth is due to some bad > > interaction between burstiness caused by Xen's context switching and > > dummynet. > > Could you elaborate a bit more on this? Even if dummynet can't operate > at 500Mbps, we should atleast see the same degradation in performance > right? Because of the context switching between dom0 and domU, the packets tend to come out in a more bursty fashion. It's conceivable that this might cause hickups. It might be worth looking at the number of interupts that are occuring, and also the Xen s/w perf counters to see domain switch rate. BTW, what Ethernet card are you using? > > Are your dom0 and domU running on the same processor? Could you try > > using hyperthreading or SMP? > > Yep, same processor. For various other reasons, I wanted to avoid SMP, > so I was running with the nosmp option. I'll try running with SMP and > post an update. That'll be interesting. Ian ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
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