Re: Interrupt Assignment on host
On 11/05/2009 09:09 PM, Erik Rull wrote: Can you describe how performance suffers? Please provide vmstat (for host int/sec) and "kvm_stat -l -f 'exits|irq_exits'" output. I'm sorry, but my target system has no python installed. Any ideas how to do that manually? Try the attached bash script. You'll want debugfs mounted on /sys/kernel/debug. -- error compiling committee.c: too many arguments to function #!/bin/bash p="/sys/kernel/debug/kvm" old_exits=0 old_irq_exits=0 while :; do exits="$(cat "$p/exits")" irq_exits="$(cat "$p/irq_exits")" d_exits=$((exits - old_exits)) d_irq_exits=$((irq_exits - old_irq_exits)) printf "%10d %10d\n" "$d_exits" "$d_irq_exits" sleep 1 old_exits="$exits" old_irq_exits="$irq_exits" done
Re: Interrupt Assignment on host
Avi Kivity wrote: On 10/28/2009 11:16 PM, Erik Rull wrote: Hi all, after several tests it seems that the interrupt assignment on the host systems influences the kvm performance drastically. If eth0, video and usb are on seperate interrupts the perfomance is way better than if they are shared (that means on the same one). Normally this should not matter. But why is it within kvm? Does kvm somehow hook up into the interrupt service routines? No. My guest is Windows XP SP3. Can you describe how performance suffers? Please provide vmstat (for host int/sec) and "kvm_stat -l -f 'exits|irq_exits'" output. I'm sorry, but my target system has no python installed. Any ideas how to do that manually? - Erik -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Interrupt Assignment on host
On 10/28/2009 11:16 PM, Erik Rull wrote: Hi all, after several tests it seems that the interrupt assignment on the host systems influences the kvm performance drastically. If eth0, video and usb are on seperate interrupts the perfomance is way better than if they are shared (that means on the same one). Normally this should not matter. But why is it within kvm? Does kvm somehow hook up into the interrupt service routines? No. My guest is Windows XP SP3. Can you describe how performance suffers? Please provide vmstat (for host int/sec) and "kvm_stat -l -f 'exits|irq_exits'" output. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Interrupt Assignment on host
Hi all, after several tests it seems that the interrupt assignment on the host systems influences the kvm performance drastically. If eth0, video and usb are on seperate interrupts the perfomance is way better than if they are shared (that means on the same one). Normally this should not matter. But why is it within kvm? Does kvm somehow hook up into the interrupt service routines? My guest is Windows XP SP3. Best regards, Erik -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
