[root@quaco ~]# perf ftrace latency -T handle_mm_fault -a ^C# DURATION | COUNT | GRAPH | 0 - 1 us | 62 | ###### | 1 - 2 us | 88 | ######## | 2 - 4 us | 222 | ##################### | 4 - 8 us | 72 | ###### | 8 - 16 us | 25 | ## | 16 - 32 us | 4 | | 32 - 64 us | 2 | | 64 - 128 us | 0 | | 128 - 256 us | 0 | | 256 - 512 us | 0 | | 512 - 1024 us | 0 | | 1 - 2 ms | 0 | | 2 - 4 ms | 0 | | 4 - 8 ms | 0 | | 8 - 16 ms | 0 | | 16 - 32 ms | 0 | | 32 - 64 ms | 0 | | 64 - 128 ms | 0 | | 128 - 256 ms | 0 | | 256 - 512 ms | 0 | | 512 - 1024 ms | 0 | | 1 - ... s | 0 | | [root@quaco ~]# [root@quaco ~]# perf ftrace latency -T handle_mm_fault -a sleep 5 # DURATION | COUNT | GRAPH | 0 - 1 us | 154 | ######## | 1 - 2 us | 168 | ######## | 2 - 4 us | 357 | ################## | 4 - 8 us | 143 | ####### | 8 - 16 us | 46 | ## | 16 - 32 us | 10 | | 32 - 64 us | 1 | | 64 - 128 us | 0 | | 128 - 256 us | 0 | | 256 - 512 us | 0 | | 512 - 1024 us | 0 | | 1 - 2 ms | 0 | | 2 - 4 ms | 0 | | 4 - 8 ms | 0 | | 8 - 16 ms | 0 | | 16 - 32 ms | 0 | | 32 - 64 ms | 0 | | 64 - 128 ms | 0 | | 128 - 256 ms | 0 | | 256 - 512 ms | 0 | | 512 - 1024 ms | 0 | | 1 - ... s | 0 | | [root@quaco ~]# [root@quaco ~]# [root@quaco ~]# perf ftrace latency --bpf -T handle_mm_fault -a Error: unknown option `bpf' Usage: perf ftrace [] [] or: perf ftrace [] -- [] [] or: perf ftrace {trace|latency} [] [] or: perf ftrace {trace|latency} [] -- [] [] -b, --use-bpf Use BPF to measure function latency -n, ----use-nsec Use nano-second histogram -T, --trace-funcs Show latency of given function [root@quaco ~]# perf ftrace latency --use-bpf -T handle_mm_fault -a ^C# DURATION | COUNT | GRAPH | 0 - 1 us | 227 | ################# | 1 - 2 us | 293 | ###################### | 2 - 4 us | 62 | #### | 4 - 8 us | 9 | | 8 - 16 us | 5 | | 16 - 32 us | 1 | | 32 - 64 us | 0 | | 64 - 128 us | 0 | | 128 - 256 us | 0 | | 256 - 512 us | 0 | | 512 - 1024 us | 0 | | 1 - 2 ms | 0 | | 2 - 4 ms | 0 | | 4 - 8 ms | 0 | | 8 - 16 ms | 0 | | 16 - 32 ms | 0 | | 32 - 64 ms | 0 | | 64 - 128 ms | 0 | | 128 - 256 ms | 0 | | 256 - 512 ms | 0 | | 512 - 1024 ms | 0 | | 1 - ... s | 0 | | [root@quaco ~]# perf ftrace latency --use-bpf -T handle_mm_fault -a sleep 5 # DURATION | COUNT | GRAPH | 0 - 1 us | 313 | ############## | 1 - 2 us | 567 | ######################### | 2 - 4 us | 109 | #### | 4 - 8 us | 21 | | 8 - 16 us | 6 | | 16 - 32 us | 4 | | 32 - 64 us | 0 | | 64 - 128 us | 0 | | 128 - 256 us | 0 | | 256 - 512 us | 0 | | 512 - 1024 us | 0 | | 1 - 2 ms | 0 | | 2 - 4 ms | 0 | | 4 - 8 ms | 0 | | 8 - 16 ms | 0 | | 16 - 32 ms | 0 | | 32 - 64 ms | 0 | | 64 - 128 ms | 0 | | 128 - 256 ms | 0 | | 256 - 512 ms | 0 | | 512 - 1024 ms | 0 | | 1 - ... s | 0 | | [root@quaco ~]#