Documentation: Fix the wrong command echo -1 > set_ftrace_pid for cleaning the filter.

The command `echo > set_ftrace_pid` should be used to clean the filter quietly.
because the command `echo -1 >  set_ftrace_pid` will output the following:
"bash: echo: write error: Invalid argument".

so update the file Documentation/trace/ftrace.txt.

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Wang Long 2015-02-05 05:16:14 +00:00 committed by Jonathan Corbet
parent 67c47cfcc7
commit 52e68924df

View File

@ -1740,7 +1740,7 @@ no pid
yum-updatesd-3111 [003] 1637.254683: lock_hrtimer_base <-hrtimer_try_to_cancel
yum-updatesd-3111 [003] 1637.254685: fget_light <-do_sys_poll
yum-updatesd-3111 [003] 1637.254686: pipe_poll <-do_sys_poll
# echo -1 > set_ftrace_pid
# echo > set_ftrace_pid
# cat trace |head
# tracer: function
#