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Commit 0a5d6490 authored by Jody McIntyre's avatar Jody McIntyre Committed by Ingo Molnar
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tracing: Documentation / sample code fixes for tracepoints 



Fix the tracepoint documentation to refer to "tracepoint-sample"
instead of "tracepoint-example" to match what actually exists;
fix the directory, and clarify how to compile.

Change every instance of "example" in the sample tracepoint code
to "sample" for consistency.

Signed-off-by: default avatarJody McIntyre <scjody@sun.com>
Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: torvalds@linux-foundation.org
LKML-Reference: <20090324200027.GH8294@clouds>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a524446f

Documentation/tracepoints.txt

+7 −6
Original line number Diff line number Diff line
@@ -103,13 +103,14 @@ used to export the defined tracepoints. 


* Probe / tracepoint example



See the example provided in samples/tracepoints/src

See the example provided in samples/tracepoints



Compile them with your kernel.

Compile them with your kernel.  They are built during 'make' (not

'make modules') when CONFIG_SAMPLE_TRACEPOINTS=m.



Run, as root :

modprobe tracepoint-example (insmod order is not important)

modprobe tracepoint-probe-example

cat /proc/tracepoint-example (returns an expected error)

rmmod tracepoint-example tracepoint-probe-example

modprobe tracepoint-sample (insmod order is not important)

modprobe tracepoint-probe-sample

cat /proc/tracepoint-sample (returns an expected error)

rmmod tracepoint-sample tracepoint-probe-sample

dmesg

samples/tracepoints/tracepoint-sample.c

+12 −12
Original line number Diff line number Diff line 
/* tracepoint-sample.c

 *

 * Executes a tracepoint when /proc/tracepoint-example is opened.

 * Executes a tracepoint when /proc/tracepoint-sample is opened.

 *

 * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

 *
@@ -16,7 +16,7 @@ 
DEFINE_TRACE(subsys_event);

DEFINE_TRACE(subsys_eventb);



struct proc_dir_entry *pentry_example;

struct proc_dir_entry *pentry_sample;



static int my_open(struct inode *inode, struct file *file)

{
@@ -32,25 +32,25 @@ static struct file_operations mark_ops = { 
	.open = my_open,

};



static int __init example_init(void)

static int __init sample_init(void)

{

	printk(KERN_ALERT "example init\n");

	pentry_example = proc_create("tracepoint-example", 0444, NULL,

	printk(KERN_ALERT "sample init\n");

	pentry_sample = proc_create("tracepoint-sample", 0444, NULL,

		&mark_ops);

	if (!pentry_example)

	if (!pentry_sample)

		return -EPERM;

	return 0;

}



static void __exit example_exit(void)

static void __exit sample_exit(void)

{

	printk(KERN_ALERT "example exit\n");

	remove_proc_entry("tracepoint-example", NULL);

	printk(KERN_ALERT "sample exit\n");

	remove_proc_entry("tracepoint-sample", NULL);

}



module_init(example_init)

module_exit(example_exit)

module_init(sample_init)

module_exit(sample_exit)



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Mathieu Desnoyers");

MODULE_DESCRIPTION("Tracepoint example");
 
MODULE_DESCRIPTION("Tracepoint sample");