Perf不支持某些性能事件

Question

我想用perf。

测量我的应用程序的停滞周期

当我尝试：perf stat -B dd if=/dev/zero of=/dev/null count=1000000

时

1000000+0 records in
1000000+0 records out
512000000 bytes (512 MB) copied, 0.218456 s, 2.3 GB/s

Performance counter stats for 'dd if=/dev/zero of=/dev/null count=1000000':

218.420011 task-clock                #    0.995 CPUs utilized          
25 context-switches          #    0.000 M/sec                  
1 CPU-migrations            #    0.000 M/sec                  
255 page-faults               #    0.001 M/sec                  
821,183,099 cycles                    #    3.760 GHz                    
<not supported> stalled-cycles-frontend 
<not supported> stalled-cycles-backend  
1,526,427,190 instructions              #    1.86  insns per cycle        
292,281,624 branches                  # 1338.163 M/sec                  
1,013,837 branch-misses             #    0.35% of all branches        

0.219551862 seconds time elapsed

正如你所看到的，我正在寻找陷入停滞的周期*事件。我无法在网上找到解决方案或解释。

我的内核版本是3.2.0-59，perf版本是3.2.54，我的CPU是i7-3770。