2009/2/25 Dor Laor <dlaor@xxxxxxxxxx>: > Alpár Török wrote: >> >> Hi, >> >> First of all please allow me to salute the community since this is my >> first post. >> > > Congratulations, hoping for the next ones :) >> >> Now my problem. I have been using KVM to conduct tests for various >> software on windows, so far it worked out just fine. I use savevm and >> loadvm to assure that the VM is in the same state for each test. I do >> a savevm manually, then start the automatic tests. >> >> Lately i was trying to optimize parts of my tests, to increase the >> throughput. >> >> First the network I/O was slow with the default device, and i needed >> to copy some files to the VM for each test. The virtio network driver >> was fast, but with my bridge networking, on Win XP, after starting the >> VM with loadvm. This isn't such a big issue since i then started using >> e1000 device, and speed increased. I am not sure just how much would >> virtio be faster, so the question remains : Doesn't virtio work with >> loadvm/savevm, or (most probably) am i doing something wrong? >> > > Indeed virtio performs better than e1000. > It should work, please provide host kernel version, kvm version, virtio net > version and > windows guest type. Also the cmdline and monitor command will help. kernel is 2.6.25.16-0.1-default of openSuse 11.0 KVM version is 63-31.1 (also shipped with the distribution) I don't know what version i have tried beafore, i tried to repeat the scenario, and coudn't even install the latest version i have just downloaded (5.1.2008.1229) , and failes with : device coudn't be started (code=10) , it's strange. The guest is Xindows Xp SP2 the command line is : -net nic,ifname=virtio -net tap,tap0 -m 256 -loadvm state here is my small script that initializes the network (please note that i need the machines to be isolated from the external world) vconfig add eth0 2 brctl addbr br0 brctl addif br0 eth0.2 for ((i=0; i < 2 ; i++)); do echo -n "Setting up $i" tunctl -u 1 -t tap$i brctl addif br0 tap$i ifconfig tap$i up promisc done ifconfig br0 10.0.1.1 netmask 255.255.255.0 Changing parts of this setup can also make networking not work after savevm / loadvm , not even with e1000, in some cases, the network stops working only after the host is restarted (the network configuration re - created). > >> The second issue, even a greather one, is disk access speed in the VM. >> Again i have looked at virtio, but it seems that there is no Win >> direver. Is that so? What can i do to improove disk access >> performance? >> >> > > We have beta code for windows pv block. We plan to publish them as soon > they will be rock stable. Scsi emulation also exist but might not be 100% > stable. Where can i find code or binaries? In my case. If it speeds things up, more than it makes them crash, i won't mind using it, and could probably get you some debug data on those crashes, or help in other similar ways. >> >> The final issue isn't related to performance. With the e1000 device, >> accessing or writing files on a samba share from the host failes >> saying that the file doesn't exists, (the file exists, i am sure). >> This doesn't happen all that often, less than 1% of the time, but it's >> rather anolying because it influences the tests. it seems to be happen >> randomly, i caoudm't identify a factor that might be causing it. >> >> > > Seems like a samba related bug and not necessarily network bug. any advice on how could i gather debugging information? I must be able to include this into my test cases, because i can't reproduce it by hand, i have to trap the problem, when it happens. >> >> Thank you in advance for your advices. >> >> -- >> Alpar Torok >> -- >> To unsubscribe from this list: send the line "unsubscribe kvm" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- Alpar Torok -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
