Commit Graph

2 Commits

Author SHA1 Message Date
Hemant Kumar 78e6c39b23 perf kvm/powerpc: Add support for HCALL reasons
Powerpc provides hcall events that also provides insights into guest
behaviour. Enhance perf kvm stat to record and analyze hcall events.

 - To trace hcall events :
  perf kvm stat record

 - To show the results :
  perf kvm stat report --event=hcall

The result shows the number of hypervisor calls from the guest grouped
by their respective reasons displayed with the frequency.

This patch makes use of two additional tracepoints
"kvm_hv:kvm_hcall_enter" and "kvm_hv:kvm_hcall_exit". To map the hcall
codes to their respective names, it needs a mapping. Such mapping is
added in this patch in book3s_hcalls.h.

 # pgrep qemu
A sample output :
19378
60515

2 VMs running.

 # perf kvm stat record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data.guest (39624
samples) ]

 # perf kvm stat report -p 60515 --event=hcall

Analyze events for all VMs, all VCPUs:

    HCALL-EVENT Samples Samples% Time% MinTime MaxTime  AvgTime

          H_IPI     822  66.08% 88.10% 0.63us  11.38us 2.05us (+- 1.42%)
     H_SEND_CRQ     144  11.58%  3.77% 0.41us   0.88us 0.50us (+- 1.47%)
   H_VIO_SIGNAL     118   9.49%  2.86% 0.37us   0.83us 0.47us (+- 1.43%)
H_PUT_TERM_CHAR      76   6.11%  2.07% 0.37us   0.90us 0.52us (+- 2.43%)
H_GET_TERM_CHAR      74   5.95%  2.23% 0.37us   1.70us 0.58us (+- 4.77%)
         H_RTAS       6   0.48%  0.85% 1.10us   9.25us 2.70us (+-48.57%)
      H_PERFMON       4   0.32%  0.12% 0.41us   0.96us 0.59us (+-20.92%)

Total Samples:1244, Total events handled time:1916.69us.

Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Scott  Wood <scottwood@freescale.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1453962787-15376-4-git-send-email-hemant@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-01-29 17:49:54 -03:00
Hemant Kumar 066d3593e1 perf kvm/powerpc: Port perf kvm stat to powerpc
perf kvm can be used to analyze guest exit reasons. This support already
exists in x86. Hence, porting it to powerpc.

 - To trace KVM events :
  perf kvm stat record
  If many guests are running, we can track for a specific guest by using
  --pid as in : perf kvm stat record --pid <pid>

 - To see the results :
  perf kvm stat report

The result shows the number of exits (from the guest context to
host/hypervisor context) grouped by their respective exit reasons with
their frequency.

Since, different powerpc machines have different KVM tracepoints, this
patch discovers the available tracepoints dynamically and accordingly
looks for them. If any single tracepoint is not present, this support
won't be enabled for reporting. To record, this will fail if any of the
events we are looking to record isn't available.  Right now, its only
supported on PowerPC Book3S_HV architectures.

To analyze the different exits, group them and present them (in a slight
descriptive way) to the user, we need a mapping between the "exit code"
(dumped in the kvm_guest_exit tracepoint data) and to its related
Interrupt vector description (exit reason). This patch adds this mapping
in book3s_hv_exits.h.

It records on two available KVM tracepoints for book3s_hv:

"kvm_hv:kvm_guest_exit" and "kvm_hv:kvm_guest_enter".

Here is a sample o/p:
 # pgrep qemu
19378
60515

2 Guests are running on the host.

 # perf kvm stat record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.153 MB perf.data.guest (39624
samples) ]

 # perf kvm stat report -p 60515

Analyze events for pid(s) 60515, all VCPUs:

     VM-EXIT Samples Samples% Time% MinTime    MaxTime  Avg time

       SYSCALL  9141  63.67%  7.49% 1.26us   5782.39us    9.87us (+- 6.46%)
H_DATA_STORAGE  4114  28.66%  5.07% 1.72us   4597.68us   14.84us (+-20.06%)
HV_DECREMENTER   418   2.91%  4.26% 0.70us  30002.22us  122.58us (+-70.29%)
      EXTERNAL   392   2.73%  0.06% 0.64us    104.10us    1.94us (+-18.83%)
RETURN_TO_HOST   287   2.00% 83.11% 1.53us 124240.15us 3486.52us (+-16.81%)
H_INST_STORAGE     5   0.03%  0.00% 1.88us      3.73us    2.39us (+-14.20%)

Total Samples:14357, Total events handled time:1203918.42us.

Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Scott  Wood <scottwood@freescale.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1453962787-15376-3-git-send-email-hemant@linux.vnet.ibm.com
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-01-29 17:49:54 -03:00