[RFC][PATCH] KVM: perf: a smart tool to analyse kvm events

[Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>]

This tool is very like xenoprof(if i remember correctly), and traces kvm events
smartly. currently, it supports vmexit/mmio/ioport events.

Usage:
- to trace kvm events:
# ./perf kvm-events record

- show the result
# ./perf kvm-events report

Some output are as follow:
# ./perf kvm-events report
  Warning: Error: expected type 5 but read 4
  Warning: Error: expected type 5 but read 0
  Warning: unknown op '}'


Analyze events for all VCPUs:

             VM-EXIT    Samples      Samples%         Time%        Avg time

         APIC_ACCESS     438107        44.89%         6.20%        17.91us
  EXTERNAL_INTERRUPT     219226        22.46%         8.01%        46.20us
      IO_INSTRUCTION     122651        12.57%         1.88%        19.44us
       EPT_VIOLATION      83110         8.52%         1.36%        20.75us
   PENDING_INTERRUPT      37055         3.80%         0.16%         5.38us
               CPUID      32718         3.35%         0.08%         3.15us
       EXCEPTION_NMI      23601         2.42%         0.17%         8.87us
                 HLT      15424         1.58%        82.12%      6735.06us
           CR_ACCESS       4089         0.42%         0.02%         6.08us

Total Samples:975981, Total events handled time:126502464.88us.

The default event to be analysed is vmexit, we can use --event to specify it,
for example, if we want to trace mmio event:
# ./perf kvm-events report --event mmio
  Warning: Error: expected type 5 but read 4
  Warning: Error: expected type 5 but read 0
  Warning: unknown op '}'


Analyze events for all VCPUs:

         MMIO Access    Samples      Samples%         Time%        Avg time

        0xfee00380:W     196589        64.95%        70.01%         3.83us
        0xfee00310:W      35356        11.68%         6.48%         1.97us
        0xfee00300:W      35356        11.68%        16.37%         4.97us
        0xfee00300:R      35356        11.68%         7.14%         2.17us

Total Samples:302657, Total events handled time:1074746.01us.

We can use --vcpu to specify which vcpu is traced:
root@localhost perf]# ./perf kvm-events report --event mmio --vcpu 1
  Warning: Error: expected type 5 but read 4
  Warning: Error: expected type 5 but read 0
  Warning: unknown op '}'


Analyze events for VCPU 1:

         MMIO Access    Samples      Samples%         Time%        Avg time

        0xfee00380:W      58041        71.20%        74.90%         3.70us
        0xfee00310:W       7826         9.60%         5.28%         1.93us
        0xfee00300:W       7826         9.60%        13.82%         5.06us
        0xfee00300:R       7826         9.60%         6.01%         2.20us

Total Samples:81519, Total events handled time:286577.81us.

And, '--key' is used to sort the result, the possible value sample (default,
the result is sorted by samples number), time(the result is sorted by time%):
# ./perf kvm-events report --key time
  Warning: Error: expected type 5 but read 4
  Warning: Error: expected type 5 but read 0
  Warning: unknown op '}'


Analyze events for all VCPUs:

             VM-EXIT    Samples      Samples%         Time%        Avg time

                 HLT      15424         1.58%        82.12%      6735.06us
  EXTERNAL_INTERRUPT     219226        22.46%         8.01%        46.20us
         APIC_ACCESS     438107        44.89%         6.20%        17.91us
      IO_INSTRUCTION     122651        12.57%         1.88%        19.44us
       EPT_VIOLATION      83110         8.52%         1.36%        20.75us
       EXCEPTION_NMI      23601         2.42%         0.17%         8.87us
   PENDING_INTERRUPT      37055         3.80%         0.16%         5.38us
               CPUID      32718         3.35%         0.08%         3.15us
           CR_ACCESS       4089         0.42%         0.02%         6.08us

Total Samples:975981, Total events handled time:126502464.88us.

I hope guys will like it and any comments are welcome! :)