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linux下性能分析---perf

perf是Linux kernel自带的系统性能优化工具

perf

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$perf

usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS]

The most commonly used perf commands are:
annotate Read perf.data (created by perf record) and display annotated code
archive Create archive with object files with build-ids found in perf.data file
bench General framework for benchmark suites
buildid-cache Manage build-id cache.
buildid-list List the buildids in a perf.data file
c2c Shared Data C2C/HITM Analyzer.
config Get and set variables in a configuration file.
data Data file related processing
diff Read perf.data files and display the differential profile
evlist List the event names in a perf.data file
ftrace simple wrapper for kernel's ftrace functionality
inject Filter to augment the events stream with additional information
kallsyms Searches running kernel for symbols
kmem Tool to trace/measure kernel memory properties
kvm Tool to trace/measure kvm guest os
list List all symbolic event types
lock Analyze lock events
mem Profile memory accesses
record Run a command and record its profile into perf.data
report Read perf.data (created by perf record) and display the profile
sched Tool to trace/measure scheduler properties (latencies)
script Read perf.data (created by perf record) and display trace output
stat Run a command and gather performance counter statistics
test Runs sanity tests.
timechart Tool to visualize total system behavior during a workload
top System profiling tool.
version display the version of perf binary
probe Define new dynamic tracepoints
trace strace inspired tool

See 'perf help COMMAND' for more information on a specific command.

常用参数

参数描述
top动态时实追踪显示占用CPU较高的进程
record由于top只能实时查看不能保存,不便于事后分析,用此参数保存追踪的内容,文件名为perf.data
report重放perf.data的内容

示例

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#记录
$sudo perf record -g -p <pid>
#回放
$sudo perf report

KVM

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# perf kvm stat record -a sleep 100
# perf kvm stat report

Analyze events for all VMs, all VCPUs:

VM-EXIT Samples Samples% Time% Min Time Max Time Avg time

MSR_WRITE 42521 53.32% 0.06% 0.50us 52.94us 1.71us ( +- 0.48% )
HLT 15885 19.92% 99.89% 0.63us 17539.26us 8224.34us ( +- 0.61% )
IO_INSTRUCTION 10892 13.66% 0.03% 2.14us 47.60us 3.02us ( +- 0.48% )
APIC_WRITE 6226 7.81% 0.02% 0.52us 41.71us 3.88us ( +- 0.94% )
EXTERNAL_INTERRUPT 1965 2.46% 0.00% 0.42us 42.59us 1.46us ( +- 2.38% )
PREEMPTION_TIMER 1805 2.26% 0.00% 0.54us 16.87us 2.13us ( +- 1.59% )
EPT_MISCONFIG 302 0.38% 0.00% 0.76us 171.85us 16.38us ( +- 7.97% )
MSR_READ 132 0.17% 0.00% 0.74us 3.52us 1.56us ( +- 4.86% )
PAUSE_INSTRUCTION 16 0.02% 0.00% 0.45us 0.87us 0.66us ( +- 4.89% )

Total Samples:79744, Total events handled time:130785328.50us.
  • HLT: (halt)是由于CPU进入idle状态时,就会调用该指令把CPU挂起。这样虚拟CPU挂起后就能出让物理CPU给其它进程使用。
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  • 本文作者: Winddoing
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