使用字段分隔符选项获取时间

Question

我有一个解析linux命令perf输出的程序。 它需要使用选项-x ，（字段分隔符选项。我想使用perf提取elapsed time （不是task-time或cpu-clock ）。但是当我使用-x选项时，经过的时间不存在于输出，我找不到相应的perf事件。这是样本输出

perf stat ls
============
 Performance counter stats for 'ls':

          0.934889 task-clock (msec)         #    0.740 CPUs utilized          
                 6 context-switches          #    0.006 M/sec                  
                 0 cpu-migrations            #    0.000 K/sec                  
               261 page-faults               #    0.279 M/sec                  
         1,937,910 cycles                    #    2.073 GHz                    
   <not supported> stalled-cycles-frontend 
   <not supported> stalled-cycles-backend  
         1,616,944 instructions              #    0.83  insns per cycle        
           317,016 branches                  #  339.095 M/sec                  
            12,439 branch-misses             #    3.92% of all branches        

       0.001262625 seconds time elapsed //here we have it

现在有字段分隔符选项

perf stat -x, ls
================
2.359807,task-clock
6,context-switches
0,cpu-migrations
261,page-faults
1863028,cycles
<not supported>,stalled-cycles-frontend
<not supported>,stalled-cycles-backend
1670644,instructions
325047,branches
12251,branch-misses

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Answer 1

# perf stat ls 2>&1 >/dev/null | tail -n 2 | sed 's/ \+//' | sed 's/ /,/'

0.002272536,seconds time elapsed