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SubjectRe: [PATCH 3/3] KVM: perf: kvm events analysis tool
On 2/15/12 9:59 PM, Xiao Guangrong wrote:
>
>
> Okay, i will post the next version after collecting your new comments!
>
> Thanks for your time, David! :)
>

I had more comments, but got sidetracked and forgot to come back to
this. I still haven't looked at the code yet, but some comments from
testing:

1. The error message:
Warning: Error: expected type 5 but read 4
Warning: Error: expected type 5 but read 0
Warning: unknown op '}'

is fixed by this patch which has not yet made its way into perf:
https://lkml.org/lkml/2011/9/4/41

The most recent request:
https://lkml.org/lkml/2012/2/8/479

Arnaldo: the patch still applies cleanly (but with an offset of -2 lines).


2. negatve testing:

perf kvm-events record -e kvm:* -p 2603 -- sleep 10

Warning: Error: expected type 4 but read 7
Warning: Error: expected type 5 but read 0
Warning: failed to read event print fmt for kvm_apic
Warning: Error: expected type 4 but read 7
Warning: Error: expected type 5 but read 0
Warning: failed to read event print fmt for kvm_inj_exception
Fatal: bad op token {

If other kvm events are specified in the record line they appear to be
silently ignored in the report in which case why allow the -e option to
record?


3. What is happening for multiple VMs?

a. perf kvm-events report
data is collected for all VMs. What is displayed in the report? An
average for all VMs?

b. perf kvm-events report --vcpu 1
Does this given an average of all vcpu 1's?

Perhaps a -p option for the report to pull out events related to a
single VM. Really this could be a generic option (to perf-report and
perf-script as well) to only show/analyze events for the specified pid.
ie., data is recorded for all VMs (or system wide for the regular
perf-record) and you want to only consider events for a specific pid.
e.g., in process_sample_event() skip event if event->ip.pid !=
report_pid (works for perf code because PERF_SAMPLE_TID attribute is
always set).

David


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