Hi,

I am wondering what tools are available to troubleshoot KVM I/O problems on CentOS 5, given that the kernel is 2.6.18 with some backports to support virtualisation?

kvm_stat / kvmtrace - These seem to be available in the kvm-tools package.

ftrace related things seem not to be available.

OProfile is available, can it be used?

Also, SystemTap is available, can it be used?

Anything else?

I don't currently have any experience using any of those, except for a brief experiment with OProfile, but my impression is that it's more of an event-counting tool - I'm not sure it can time function call execution times.

Which makes me think SystemTap is better suited. However, this reference [1] makes me wonder if it can only be used with QEMU/KVM CentOS 6.

Has anyone any experience or prior art they can share or reference, specifically with profiling virtio_blk?

Thanks,

Nick

1.

BZ#632722 - This update introduces support for tracing of events within QEMU; the tracing is similar in its style to DTrace. When used in conjunction with SystemTap, it is now possible to trace internal QEMU events such as I/O operations and memory allocations

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.1_Techni...