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-rw-r--r--Documentation/tracepoints.txt21
1 files changed, 11 insertions, 10 deletions
diff --git a/Documentation/tracepoints.txt b/Documentation/tracepoints.txt
index 6f0a044f5b5e..c0e1ceed75a4 100644
--- a/Documentation/tracepoints.txt
+++ b/Documentation/tracepoints.txt
@@ -45,8 +45,8 @@ In include/trace/subsys.h :
45#include <linux/tracepoint.h> 45#include <linux/tracepoint.h>
46 46
47DECLARE_TRACE(subsys_eventname, 47DECLARE_TRACE(subsys_eventname,
48 TPPROTO(int firstarg, struct task_struct *p), 48 TP_PROTO(int firstarg, struct task_struct *p),
49 TPARGS(firstarg, p)); 49 TP_ARGS(firstarg, p));
50 50
51In subsys/file.c (where the tracing statement must be added) : 51In subsys/file.c (where the tracing statement must be added) :
52 52
@@ -66,10 +66,10 @@ Where :
66 - subsys is the name of your subsystem. 66 - subsys is the name of your subsystem.
67 - eventname is the name of the event to trace. 67 - eventname is the name of the event to trace.
68 68
69- TPPROTO(int firstarg, struct task_struct *p) is the prototype of the 69- TP_PROTO(int firstarg, struct task_struct *p) is the prototype of the
70 function called by this tracepoint. 70 function called by this tracepoint.
71 71
72- TPARGS(firstarg, p) are the parameters names, same as found in the 72- TP_ARGS(firstarg, p) are the parameters names, same as found in the
73 prototype. 73 prototype.
74 74
75Connecting a function (probe) to a tracepoint is done by providing a 75Connecting a function (probe) to a tracepoint is done by providing a
@@ -103,13 +103,14 @@ used to export the defined tracepoints.
103 103
104* Probe / tracepoint example 104* Probe / tracepoint example
105 105
106See the example provided in samples/tracepoints/src 106See the example provided in samples/tracepoints
107 107
108Compile them with your kernel. 108Compile them with your kernel. They are built during 'make' (not
109'make modules') when CONFIG_SAMPLE_TRACEPOINTS=m.
109 110
110Run, as root : 111Run, as root :
111modprobe tracepoint-example (insmod order is not important) 112modprobe tracepoint-sample (insmod order is not important)
112modprobe tracepoint-probe-example 113modprobe tracepoint-probe-sample
113cat /proc/tracepoint-example (returns an expected error) 114cat /proc/tracepoint-sample (returns an expected error)
114rmmod tracepoint-example tracepoint-probe-example 115rmmod tracepoint-sample tracepoint-probe-sample
115dmesg 116dmesg