android perf报告perf.data文件没有示例

Question

我试着在android上使用perf

android是在用户调试模式下构建的。

perf是在$ANDROID_SRC/external下用源代码构建的，我把它推送到了/data

是不是由于我没有启用内核中的一些配置或选项导致的？

还是因为缺少一些符号？

Thx

root@s3gr20m6s:/data # ./perf record -p 4003                                   
^C[ perf record: Woken up 1 times to write data ]
[perf record: Captured and wrote 0.746 MB perf.data (~32610 samples) ]

root@s3gr20m6s:/data # ./perf report                                           
Error:
The perf.data file has no samples!
# ========
# captured on: Fri Dec 31 20:03:35 1999
# hostname : localhost
# os release : 3.14.41-i386-00011-g653e4cf
# perf version : perf.3.12_android
# arch : i686
# nrcpus online : 4
# nrcpus avail : 4
# cpudesc : Genuine Intel(R) CPU @ 728
# total memory : 948656 kB
# cmdline : /data/perf record -R -p 4003 
# event : name = cycles, type = 0, config = 0x0, config1 = 0x0,    config2 = 0x0, excl_usr = 0, excl_kern = 0, excl_host = 0, excl_guest = 1, precise_ip = 0, attr_mmap2 = 0, attr_mmap  = 1, attr_mmap_data = 0
# HEADER_CPU_TOPOLOGY info available, use -I to display
# pmu mappings: cpu = 4, software = 1, tracepoint = 2, breakpoint = 5

The perf.data file has no samples!

Answer 1

尝试添加-e cpu-clock可能无法访问硬件分析事件，只能使用软事件。我至少在VM上看到过这种情况。