Hi All, I find a problem when I test the IPC of the kvm vcpu. My question is that when the thread is a vcpu, whether the instructions we get from perf stat includes the part spending on the time vcpu had enter vmx or else it only includes the time vm-exit. I run NPB benchmark in the KVM which owns 4 vcpu and I use the following command to get the IPC information of vcpu thread. thread 3117 is the qemu-io thread, 3118,3119,3120,3121 are the vcpu thread. I am curious that the why the IPC is so slow when the guest is running a cpu-intensive application. Here below is some output of my tests. 1." perf stat -t 3121" run for 1 s , then get the following result. [root@wenfedora hcfs]# perf stat -t 3121 ^C Performance counter stats for thread id '3121': 977.620697 task-clock-msecs # 0.999 CPUs 103 context-switches # 0.000 M/sec 0 CPU-migrations # 0.000 M/sec 0 page-faults # 0.000 M/sec 3005826152 cycles # 3074.634 M/sec 825271483 instructions # 0.275 IPC 140665441 branches # 143.885 M/sec 11731765 branch-misses # 8.340 % 256884 cache-references # 0.263 M/sec 3102 cache-misses # 0.003 M/sec 0.978720288 seconds time elapsed 2.output for "ps -eLf | grep qemu" qemu 3117 1 3118 94 6 11:22 ? 00:23:02 /usr/bin/qemu-kvm -S -M pc-0.13 -enable-kvm -m 3869 -smp 4,sockets=4,cores=1,threads=1 -name c1 -uuid 1f335024-45fb-fadb-db63-34a64db9840d -nodefconfig -nodefaults -chardev socket,id=monitor,path=/var/li qemu 3117 1 3119 94 6 11:22 ? 00:22:59 /usr/bin/qemu-kvm -S -M pc-0.13 -enable-kvm -m 3869 -smp 4,sockets=4,cores=1,threads=1 -name c1 -uuid 1f335024-45fb-fadb-db63-34a64db9840d -nodefconfig -nodefaults -chardev socket,id=monitor,path=/var/li qemu 3117 1 3120 94 6 11:22 ? 00:23:00 /usr/bin/qemu-kvm -S -M pc-0.13 -enable-kvm -m 3869 -smp 4,sockets=4,cores=1,threads=1 -name c1 -uuid 1f335024-45fb-fadb-db63-34a64db9840d -nodefconfig -nodefaults -chardev socket,id=monitor,path=/var/li qemu 3117 1 3121 94 6 11:22 ? 00:23:00 /usr/bin/qemu-kvm -S -M pc-0.13 -enable-kvm -m 3869 -smp 4,sockets=4,cores=1,threads=1 -name c1 -uuid 1f335024-45fb-fadb-db63-34a64db9840d -nodefconfig -nodefaults -chardev socket,id=monitor,path=/var/li Thanks, Chengjian -- 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
