Hi, Minqiang On 4/22/13 22:49 , "Yangminqiang" <yangminqiang@xxxxxxxxxx> wrote: >HI Tomoki, > >Thanks for you config file, but it is for linux-3.5-rc4, but the patches >you >posted to the community was based on linux-3.6 as described in the >following >link. > http://thread.gmane.org/gmane.linux.kernel/1353803 >I also tested the config file on linux-3.6, still can not work. Ah, that config was for patch v1. Unfortunately I lost my config for 3.6, however it is not much different from one I used for in 3.6 + patch v2. (I just did `make oldconfig'). Please refer slides for the command lines information: http://events.linuxfoundation.org/images/stories/pdf/lcna_co2012_sekiyama.p df Could you confirm that the VM is really running on the slave core? The qemu-kvm process should use only several %CPU even while the guest is running infinite loop. And running infinite loop on HOST may help to avoid cores going into power saving... >BTW, I notice your benchmark result in your slides, which shows that >the throughput of a 10Gbps NIC exceeds 10Gbps? How did that happen? That's because I measured throughput between host and guest via the internal switch of SR-IOV 10G NIC, which is only limited by NIC's controller chip performance and the bus speed. >My benchmark also shows a interesting data: the throughput of a pass- >through device is higher than bare-mental sometime.(I use NetPIPE) Thanks, Tomoki Sekiyama >Thanks a lot. > > >Yang Minqiang > >> -----Original Message----- >> From: Tomoki Sekiyama [mailto:tomoki.sekiyama@xxxxxxx] >> Sent: Thursday, April 11, 2013 4:37 AM >> To: Yangminqiang >> Cc: kvm@xxxxxxxxxxxxxxx; Haofeng; Luohao (brian) >> Subject: Re: KVM: kvm_set_slave_cpu: Invalid argument when trying direct >> interrupt delivery >> >> Hi, >> >> >> On 4/7/13 6:09 , "Yangminqiang" <yangminqiang@xxxxxxxxxx> wrote: >> >Hi Tomoki, >> > >> >I offline the cpu2 and cpu3 on my machine and continue to try your >>patch. >> > I run the vm without pass-through device for I only want to know the >> >interrupt latency improvement.(Am I right?) >> >> This should be OK. >> >> >my qemu parameter: >> >./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 1024 -cpu >> >qemu64,+x2apic -no-kvm-pit -serial pty -nographic -drive >> >file=/mnt/sdb/vms/testfc/testfc.qcow2,if=virtio,index=0,format=qcow2 >> >-spice >> >port=12000,addr=186.100.8.171,disable-ticketing,plaintext-channel=main, >> >pla >> >intext-channel=playback,plaintext-channel=record,image-compression=aut >> o >> >_gl >> >z -no-kvm-pit >> >> Using video (-spice) could cause a large latency, because >>non-passthrough >> devices cause larger latency with this patch. >> Please use serial console (but should avoid serial I/O while benchmark, >> because serial I/O is also non-passthrough device). >> >> You may need to turn off CPU low power features, or running some >>infinite >> loop (e.g. yes>/dev/null) to avoid cpu core from going into power saving >> mode. >> >> >> >cyclictest: >> > cyclictest -m -p 99 -n -l 100000 -h 3000 -q >> > >> > >> >but I got very bad result: >> > avg lantency: 20000+ us >> > max lantency: 50000+ us >> > >> >and got >> > >> >Message from syslogd@kvmsteven at Apr 7 05:43:30 ... >> > kernel:[ 2201.151817] BUG: soft lockup - CPU#18 stuck for 22s! >> >[qemu-system-x86:2365] >> >> This patch is not yet tested in various kernel CONFIG_* settings, and >>some >> config may cause issue like this... >> I was using Fedora-based config (attached). Could you try with this? >> >> >my setup: >> >host kernel: 3.6.0-rc4+ and your patches guest kernel: 3.6.11.1-rt32 >> >qemu: qemu-kvm-1.0 with your patch >> > >> >BTW, I am sure that my rt-kernel works well, which got 12us max latency >> >as a host OS. >> > >> >Could you please provoide me more detail about your benchmark so I >> >could reproduce your benchmark result? >> > >> >Thanks, >> >Steven > -- 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
