| ftrace.rst (6f84981772535e670e4e2df051a672af229b6694) | ftrace.rst (2abfcd293b79baf62895894fa3ea2386ffbe6338) |
|---|---|
| 1======================== 2ftrace - Function Tracer 3======================== 4 5Copyright 2008 Red Hat Inc. 6 7:Author: Steven Rostedt <srostedt@redhat.com> 8:License: The GNU Free Documentation License, Version 1.2 --- 816 unchanged lines hidden (view full) --- 825 display more detailed information about what went wrong, if 826 information is available. The tracing/error_log file is a circular 827 error log displaying a small number (currently, 8) of ftrace errors 828 for the last (8) failed commands. 829 830 The extended error information and usage takes the form shown in 831 this example:: 832 | 1======================== 2ftrace - Function Tracer 3======================== 4 5Copyright 2008 Red Hat Inc. 6 7:Author: Steven Rostedt <srostedt@redhat.com> 8:License: The GNU Free Documentation License, Version 1.2 --- 816 unchanged lines hidden (view full) --- 825 display more detailed information about what went wrong, if 826 information is available. The tracing/error_log file is a circular 827 error log displaying a small number (currently, 8) of ftrace errors 828 for the last (8) failed commands. 829 830 The extended error information and usage takes the form shown in 831 this example:: 832 |
| 833 # echo xxx > /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger | 833 # echo xxx > /sys/kernel/tracing/events/sched/sched_wakeup/trigger |
| 834 echo: write error: Invalid argument 835 | 834 echo: write error: Invalid argument 835 |
| 836 # cat /sys/kernel/debug/tracing/error_log | 836 # cat /sys/kernel/tracing/error_log |
| 837 [ 5348.887237] location: error: Couldn't yyy: zzz 838 Command: xxx 839 ^ 840 [ 7517.023364] location: error: Bad rrr: sss 841 Command: ppp qqq 842 ^ 843 844 To clear the error log, echo the empty string into it:: 845 | 837 [ 5348.887237] location: error: Couldn't yyy: zzz 838 Command: xxx 839 ^ 840 [ 7517.023364] location: error: Bad rrr: sss 841 Command: ppp qqq 842 ^ 843 844 To clear the error log, echo the empty string into it:: 845 |
| 846 # echo > /sys/kernel/debug/tracing/error_log | 846 # echo > /sys/kernel/tracing/error_log |
| 847 848Examples of using the tracer 849---------------------------- 850 851Here are typical examples of using the tracers when controlling 852them only with the tracefs interface (without using any 853user-land utilities). 854 --- 2716 unchanged lines hidden --- | 847 848Examples of using the tracer 849---------------------------- 850 851Here are typical examples of using the tracers when controlling 852them only with the tracefs interface (without using any 853user-land utilities). 854 --- 2716 unchanged lines hidden --- |