根据perf tutorials , perf stat 应该使用硬件计数器报告缓存未命中。但是，在我的系统(最新的 Arch Linux)上，它没有:
[joel@panda goog]$ perf stat ./hash
Performance counter stats for './hash':
869.447863 task-clock # 0.997 CPUs utilized
92 context-switches # 0.106 K/sec
4 cpu-migrations # 0.005 K/sec
1,041 page-faults # 0.001 M/sec
2,628,646,296 cycles # 3.023 GHz
819,269,992 stalled-cycles-frontend # 31.17% frontend cycles idle
132,355,435 stalled-cycles-backend # 5.04% backend cycles idle
4,515,152,198 instructions # 1.72 insns per cycle
# 0.18 stalled cycles per insn
1,060,739,808 branches # 1220.015 M/sec
2,653,157 branch-misses # 0.25% of all branches
0.871766141 seconds time elapsed
我错过了什么？我已经搜索了手册页和网络，但没有发现任何明显的内容。
编辑:我的 CPU 是 Intel i5 2300K，如果这很重要的话。
最佳答案
在我的系统上，Intel Xeon X5570 @ 2.93 GHz我能够得到perf stat通过像这样明确地请求这些事件来报告缓存引用和未命中
perf stat -B -e cache-references,cache-misses,cycles,instructions,branches,faults,migrations sleep 5
Performance counter stats for 'sleep 5':
10573 cache-references
1949 cache-misses # 18.434 % of all cache refs
1077328 cycles # 0.000 GHz
715248 instructions # 0.66 insns per cycle
151188 branches
154 faults
0 migrations
5.002776842 seconds time elapsed
默认事件集不包含缓存事件，匹配你的结果，不知道为什么
perf stat -B sleep 5
Performance counter stats for 'sleep 5':
0.344308 task-clock # 0.000 CPUs utilized
1 context-switches # 0.003 M/sec
0 CPU-migrations # 0.000 M/sec
154 page-faults # 0.447 M/sec
977183 cycles # 2.838 GHz
586878 stalled-cycles-frontend # 60.06% frontend cycles idle
430497 stalled-cycles-backend # 44.05% backend cycles idle
720815 instructions # 0.74 insns per cycle
# 0.81 stalled cycles per insn
152217 branches # 442.095 M/sec
7646 branch-misses # 5.02% of all branches
5.002763199 seconds time elapsed
关于linux - 为什么 perf 不报告缓存未命中？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14674463/