Thanks for the clarifications Venu. I was measuring bandwidth by checking 'kstat -n' and as you mentioned, it's probably not accurate.
Using 'netstat -k', I see that the bandwidth is capped correctly. The only problem I have now is to get the output of 'netstat -k' in plain text, instead of the curses based output. My python wrapper runs with out a terminal, as I mentioned to you in the other e-mail. Please let me know when the new bits are available. Thanks again! Pradeep > -----Original Message----- > From: venugopal iyer [mailto:venu at sun.com] > Sent: Friday, January 18, 2008 12:12 PM > To: Pradeep Padala > Cc: crossbow-discuss at opensolaris.org > Subject: Re: [crossbow-discuss] Does capping network > bandwidth work in Crossbow? > > > Hi, Pradeep: > > On Thu, 17 Jan 2008, Pradeep Padala wrote: > > > Hi, > > > > I am trying to set bandwidth caps for two zones. I created > two vnics > > and assigned them to two zones 'exclusive'ly. Then, I used the > > following commands to set the bandwidth limits > > > > #dladm modify-vnic -b 100 1 > > #dladm modify-vnic -b 900 2 > > > > and I see that they are set correctly. > > > > # dladm show-vnic > > device speed > > vnic1 e1000g0 1000 Mbps mac: 0:14:4f:8d:a9:bd > (fixed) bw limit: > > 100 Mbps cpus: 0 > > vnic2 e1000g0 1000 Mbps mac: 0:14:4f:8d:a9:be > (fixed) bw limit: > > 900 Mbps cpus: 0 > > That's right. > > > > > I am measuring the bandwidth used by a zone, by calculating tx + rx > > bytes as seen by 'kstat -n vnic?'. Is this the right way to > measure it? > > I suspect that may work. I think you might have earlier bits > that did bandwidth regulation in squeues (in IP). So, unless > the squeue always polls the vnic to get the no. of pkts per > the set limit, the numbers above might not give you the right > info. E.g packet that comes via an interrupt will update the > vnic counters and be sent upstream to the appropriate squeue, > which will enforce the limit. (This logic has changed and we > will be pushing out the latest bits on OpenSolaris shortly, > possibly in the next week. With the latest bits the above > method - kstat - should be fine; see > http://www.opensolaris.org/os/project/crossbow/Design_softringset.txt > for some info. about bandwidth control et. al.) > > > > > > I use httperf to connect to the webservers running in the > two zones, > > and I always see the bandwidth used by the zones exceeding > the limits > > often reaching 400Mbps (my workload is very network heavy). > > > > I tried using the -L option as specified in the dladm man page > > > (http://dlc.sun.com/osol/netvirt/downloads/20070214/dladm.1m.txt) to > > cap bandwidth, but I get an error. > > > > # dladm modify-vnic -b 100 -L 1 > > dladm: unrecognized option '-L' > > -L is not needed for dladm. > > > > > I am not sure whether this is the right way to cap > bandwidth. Another > > way to do it, I believe, is to use flowadm and setup flows > with limited bandwidth. > > I thought that probably uses more protocol processing than > necessary, > > since I just want to cap the full vnic bandwidth. > > > > Yes, you should just be able to set the vnic limit, if that's > sufficient. > > > > Any ideas? > > Until the new bits are made available: I haven't used > httperf, but you could try netperf and look at its results > just to check if the limit is being enforced. > > > -venu > > > > Pradeep > > > > _______________________________________________ > > crossbow-discuss mailing list > > crossbow-discuss at opensolaris.org > > http://mail.opensolaris.org/mailman/listinfo/crossbow-discuss > > >
