Re: [PATCH] Documentation / sample code fixes for tracepoints

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

* Jody McIntyre (scjody@sun.com) wrote:
> 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: Jody McIntyre <scjody@sun.com>
> 

Yes, this documentation/samples fix is indeed needed. It should go
through Ingo's tracing tree, and then also be applied to the -stable
kernels. I have verified that the samples still build correctly.

Meanwhile, I'm pulling it in the -lttng tree.

Thanks !

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

P.S. : Ah, Sun is looking at the tracepoints ? ;-)

> Index: linux-2.6/Documentation/tracepoints.txt
> ===================================================================
> --- linux-2.6.orig/Documentation/tracepoints.txt
> +++ linux-2.6/Documentation/tracepoints.txt
> @@ -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
> Index: linux-2.6/samples/tracepoints/tracepoint-sample.c
> ===================================================================
> --- linux-2.6.orig/samples/tracepoints/tracepoint-sample.c
> +++ linux-2.6/samples/tracepoints/tracepoint-sample.c
> @@ -1,6 +1,6 @@
>  /* 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");

-- 
Mathieu Desnoyers
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