perf  top
通过-e指定关注的事件，比如查看造成cache miss最多的函数排行
perf top -e cache-misses
perf top -e task-clock 
perf top -G // 得到调用关系图
perf top-e cache-misses -G // 得到调用关系图
perf top -e cycles // 指定性能事件
perf top -p 23015,32476 //查看这两个进程的cpu cycles使用情况
perf top -s comm,pid,symbol // 显示调用symbol的进程名和进程号
perf top --comms nginx,top // 仅显示属于指定进程的符号
perf top --symbols kfree // 仅显示指定的符号
 
perf stat
perf stat -e task-clock -e context-switches -p  进程号
perf stat -e stalled-cycles-frontend -p  进程号perf  stat -r  50 ls 
Perf可以帮你统计N次结果的数值波动情况：
perf stat --repeat 5 -e kmem:mm_page_pcpu_drain -e  kmem:mm_page_alloc -e kmem:mm_pagevec_free -e kmem:mm_page_free_direct ./t2  10
 
perf record -a     
perf report
 
perf record –e cpu-clock  ./t1
perf report
 
Perf list，perf 事件
使用 perf list 命令可以列出所有能够触发 perf 采样点的事件。
Hardware Event 是由 PMU 硬件产生的事件，比如 cache 命中，当您需要了解程序对硬件特性的使用情况时，便需要对这些事件进行采样；
Software Event 是内核软件产生的事件，比如进程切换，tick 数等 ;
Tracepoint event 是内核中的静态 tracepoint 所触发的事件，这些 tracepoint 用来判断程序运行期间内核的行为细节，比如 slab 分配器的分配次数等。
List of pre-defined events (to be used in -e):
   cpu-cycles OR cycles                               [Hardware event]
   instructions                                       [Hardware event]
   cache-references                                   [Hardware event]
   cache-misses                                [Hardware event]
   branch-instructions OR branches                    [Hardware event]
   branch-misses                               [Hardware event]
   bus-cycles                                         [Hardware event]
   stalled-cycles-frontend OR idle-cycles-frontend    [Hardware event]
   stalled-cycles-backend OR idle-cycles-backend      [Hardware event]
   ref-cycles                                         [Hardware event]

  cpu-clock                                   [Software event]
   task-clock                                         [Software event]
   page-faults OR faults                              [Software event]
  context-switches OR cs                      [Software event]
   cpu-migrations OR migrations                       [Software event]
   minor-faults                                       [Software event]
   major-faults                                       [Software event]
   alignment-faults                                   [Software event]
   emulation-faults                                   [Software event]  L1-dcache-loads                                    [Hardware cache event]
   L1-dcache-load-misses                              [Hardware cache event]
   L1-dcache-stores                                   [Hardware cache event]
   L1-dcache-store-misses                             [Hardware cache event]
   L1-dcache-prefetches                               [Hardware cache event]
   L1-dcache-prefetch-misses                          [Hardware cache event]
   L1-icache-loads                                    [Hardware cache event]
   L1-icache-load-misses                              [Hardware cache event]
   L1-icache-prefetches                               [Hardware cache event]
   L1-icache-prefetch-misses                          [Hardware cache event]
   LLC-loads                                          [Hardware cache event]
   LLC-load-misses                                    [Hardware cache event]
   LLC-stores                                         [Hardware cache event]
   LLC-store-misses                                   [Hardware cache event]
   LLC-prefetches                                     [Hardware cache event]
   LLC-prefetch-misses                                [Hardware cache event]
   dTLB-loads                                         [Hardware cache event]
   dTLB-load-misses                                   [Hardware cache event]
   dTLB-stores                                        [Hardware cache event]
   dTLB-store-misses                                  [Hardware cache event]
   dTLB-prefetches                                    [Hardware cache event]
   dTLB-prefetch-misses                               [Hardware cache event]  iTLB-loads                                         [Hardware cache event]
   iTLB-load-misses                                   [Hardware cache event]
   branch-loads                                       [Hardware cache event]
   branch-load-misses                                 [Hardware cache event]
   node-loads                                         [Hardware cache event]
   node-load-misses                                   [Hardware cache event]
   node-stores                                        [Hardware cache event]
   node-store-misses                                  [Hardware cache event]
   node-prefetches                                    [Hardware cache event]
   node-prefetch-misses                               [Hardware cache event]

   mem:<addr>[:access]                                [Hardware breakpoint]  sunrpc:rpc_call_status                             [Tracepoint event]
   sunrpc:rpc_bind_status                             [Tracepoint event]
   sunrpc:rpc_connect_status                          [Tracepoint event]
   sunrpc:rpc_task_begin                              [Tracepoint event]
   sunrpc:rpc_task_run_action                         [Tracepoint event]  .............