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Description of problem:
Perf kvm commond merged into Linux kernel from 2.6.32 helps to report guest kernel and user overhead, howevere, the output of perf kvm xxx on RHEL6.0, RHEL6.2 is incorrect, it is correct on upstream.
Version-Release number of selected component (if applicable):
kenrel: 2.6.32-154.el6.x86_64
How reproducible:
On upstream Linux (2.6.39-1) and RHEL6.2 (2.6.32-154.el6.x86_64 and 2.6.32-169.el6.x86_64), with an infinite loop running in guest and collect perf top data with the following command:
[root@test1 /]# perf kvm --host --guest --guestkallsyms=/guestmodules/guest.kallsyms --guestmodules=/guestmodules/guest.modules top
Take a look into the output.
Steps to Reproduce:
1. Install a guests, running an infinite loop in the guest
2. Collect perf kvm xxx top/record results on both upstream and RHEL6.2
3. compare the results
Actual results:
On upstream:
PerfTop: 1474 irqs/sec kernel:30.3% us: 1.6% guest kernel: 3.5% guest us:64.5% exact: 0.0% [1000Hz cycles], (all, 20 CPUs)
On RHEL6.2:
PerfTop: 1469 irqs/sec kernel:99.7% us: 0.3% guest kernel: 0.0% guest us: 0.0% exact: 0.0% [1000Hz cycles], (all, 20 CPUs)
Expected results:
The results should be the same
Additional info:
Used the same machine, only upgrade kernel to 2.6.39-1.