I am getting very weird profile results by running operf on linux on
the host and profiling the a kvm virtual machine running dacapo
eclipse benchmark. I am expecting a lot of time should be spent in
the qemu-system-x86_64 as the instructions from the eclipse benchmark
would be treated as part of the qemu-system-x86_64 process, but the
results tell different. any suggestions ?
CPU_CLK_UNHALTED % Module
Symbol/Functions
1054 31.49 /kvm
/kvm
645 19.27 /kvm_intel
/kvm_intel
248 7.41
/home/xtong/qemu-kvm-1.2.0/install/bin/qemu-system-x86_64
/home/xtong/qemu-kvm-1.2.0/install/bin/qemu-system-x86_64
215 6.42 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
native_write_msr_safe
101 3.02 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
native_read_msr_safe
93 2.78 /lib/x86_64-linux-gnu/libc-2.15.so
/lib/x86_64-linux-gnu/libc-2.15.so
77 2.30 /lib/x86_64-linux-gnu/libglib-2.0.so.0.3200.4
/lib/x86_64-linux-gnu/libglib-2.0.so.0.3200.4
65 1.94 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
__srcu_read_lock
48 1.43 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
__srcu_read_unlock
40 1.20 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
native_load_tr_desc
29 0.87 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
__ticket_spin_lock
25 0.75 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
guest_exit
21 0.63 /usr/lib/debug/boot/vmlinux-3.11.0-13-generic
native_load_gdt
...
Thank you.
On Wed, Jan 29, 2014 at 11:06 PM, Xin Tong <xerox.time.tech@xxxxxxxxx> wrote:
> Hi
>
> I would like to measure the performance of KVM by using hardware
> performance counters and I have some questions
>
> 1. if i want to get the amount of time spent in instruction and device
> emulation, should i use oprofile on the kvm process on the host
> machine ?
> 2. what about amount of time spent in TLB misses, kvm makes uses of
> nested page in which a tlb miss could be expensive.
> 3. are there existing ways/measurements i can look into ?
>
> Thank you
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