Re: [PATCH v8 3/3] KVM: perf: kvm events analysis tool

From: David Ahern
Date: Thu Sep 20 2012 - 09:34:35 EST


On 9/17/12 2:31 AM, Dong Hao wrote:
From: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>

Add 'perf kvm stat' support to analyze kvm vmexit/mmio/ioport smartly

Usage:
- kvm stat
run a command and gather performance counter statistics, it is the alias of
perf stat

- trace kvm events:
perf kvm stat record, or, if other tracepoints are interesting as well, we
can append the events like this:
perf kvm stat record -e timer:* -a

If many guests are running, we can track the specified guest by using -p or
--pid, -a is used to track events generated by all guests.

- show the result:
perf kvm stat report

The output example is following:
# pgrep qemu
13005
13059

total 2 guests are running on the host

Then, track the guest whose pid is 13059:
# ./perf kvm stat record -p 13059
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.253 MB perf.data.guest (~11065 samples) ]

See the vmexit events:
# ./perf kvm stat report --event=vmexit


Analyze events for all VCPUs:

VM-EXIT Samples Samples% Time% Avg time

APIC_ACCESS 460 70.55% 0.01% 22.44us ( +- 1.75% )
HLT 93 14.26% 99.98% 832077.26us ( +- 10.42% )
EXTERNAL_INTERRUPT 64 9.82% 0.00% 35.35us ( +- 14.21% )
PENDING_INTERRUPT 24 3.68% 0.00% 9.29us ( +- 31.39% )
CR_ACCESS 7 1.07% 0.00% 8.12us ( +- 5.76% )
IO_INSTRUCTION 3 0.46% 0.00% 18.00us ( +- 11.79% )
EXCEPTION_NMI 1 0.15% 0.00% 5.83us ( +- -nan% )

Total Samples:652, Total events handled time:77396109.80us.

See the mmio events:
# ./perf kvm stat report --event=mmio


Analyze events for all VCPUs:

MMIO Access Samples Samples% Time% Avg time

0xfee00380:W 387 84.31% 79.28% 8.29us ( +- 3.32% )
0xfee00300:W 24 5.23% 9.96% 16.79us ( +- 1.97% )
0xfee00300:R 24 5.23% 7.83% 13.20us ( +- 3.00% )
0xfee00310:W 24 5.23% 2.93% 4.94us ( +- 3.84% )

Total Samples:459, Total events handled time:4044.59us.

See the ioport event:
# ./perf kvm stat report --event=ioport


Analyze events for all VCPUs:

IO Port Access Samples Samples% Time% Avg time

0xc050:POUT 3 100.00% 100.00% 13.75us ( +- 10.83% )

Total Samples:3, Total events handled time:41.26us.

And, --vcpu is used to track the specified vcpu and --key is used to sort the
result:
# ./perf kvm stat report --event=vmexit --vcpu=0 --key=time


Analyze events for VCPU 0:

VM-EXIT Samples Samples% Time% Avg time

HLT 27 13.85% 99.97% 405790.24us ( +- 12.70% )
EXTERNAL_INTERRUPT 13 6.67% 0.00% 27.94us ( +- 22.26% )
APIC_ACCESS 146 74.87% 0.03% 21.69us ( +- 2.91% )
IO_INSTRUCTION 2 1.03% 0.00% 17.77us ( +- 20.56% )
CR_ACCESS 2 1.03% 0.00% 8.55us ( +- 6.47% )
PENDING_INTERRUPT 5 2.56% 0.00% 6.27us ( +- 3.94% )

Total Samples:195, Total events handled time:10959950.90us.

[ Dong Hao <haodong@xxxxxxxxxxxxxxxxxx>
Runzhen Wang <runzhen@xxxxxxxxxxxxxxxxxx>:

- rebase it on current acme's tree

- fix the compiling-error on i386

]

Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dong Hao <haodong@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Runzhen Wang <runzhen@xxxxxxxxxxxxxxxxxx>
---
tools/perf/Documentation/perf-kvm.txt | 30 ++-
tools/perf/MANIFEST | 3 +
tools/perf/builtin-kvm.c | 840 ++++++++++++++++++++++++++++++++-
tools/perf/util/header.c | 59 +++-
tools/perf/util/header.h | 1 +
tools/perf/util/thread.h | 2 +
6 files changed, 929 insertions(+), 6 deletions(-)


Acked-by: David Ahern <dsahern@xxxxxxxxx>

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