Re: [PATCH 1/3] ftrace: rename trace_entries to buffer_size

[Frédéric Weisbecker]

2008/11/12 Steven Rostedt <rostedt@xxxxxxxxxxx>:
> Impact: rename of debugfs file trace_entries to buffer_size
>
> The original ftrace had fixed size entries, and the number of entries
> was shown and modified via the file called trace_entries. By converting
> to the unified trace buffer, we now allow for variable size entries
> which makes the meaning of trace_entries pointless.
>
> Since trace_size might be confused to the size of the trace, this patch
> names it "buffer_size" (thanks to Arjan van de Ven for this idea).
>
> Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx>
> ---
>  Documentation/ftrace.txt |   18 +++++++++---------
>  kernel/trace/trace.c     |    4 ++--
>  2 files changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt
> index 9cc4d68..58cba1f 100644
> --- a/Documentation/ftrace.txt
> +++ b/Documentation/ftrace.txt
> @@ -94,7 +94,7 @@ of ftrace. Here is a list of some of the key files:
>                only be recorded if the latency is greater than
>                the value in this file. (in microseconds)
>
> -  trace_entries: This sets or displays the number of bytes each CPU
> +  buffer_size: This sets or displays the number of bytes each CPU
>                buffer can hold. The tracer buffers are the same size
>                for each CPU. The displayed number is the size of the
>                 CPU buffer and not total size of all buffers. The
> @@ -1299,13 +1299,13 @@ trace entries
>  -------------
>
>  Having too much or not enough data can be troublesome in diagnosing
> -an issue in the kernel. The file trace_entries is used to modify
> +an issue in the kernel. The file buffer_size is used to modify
>  the size of the internal trace buffers. The number listed
>  is the number of entries that can be recorded per CPU. To know
>  the full size, multiply the number of possible CPUS with the
>  number of entries.
>
> - # cat /debug/tracing/trace_entries
> + # cat /debug/tracing/buffer_size
>  65620
>
>  Note, to modify this, you must have tracing completely disabled. To do that,
> @@ -1313,8 +1313,8 @@ echo "nop" into the current_tracer. If the current_tracer is not set
>  to "nop", an EINVAL error will be returned.
>
>  # echo nop > /debug/tracing/current_tracer
> - # echo 100000 > /debug/tracing/trace_entries
> - # cat /debug/tracing/trace_entries
> + # echo 100000 > /debug/tracing/buffer_size
> + # cat /debug/tracing/buffer_size
>  100045
>
>
> @@ -1323,8 +1323,8 @@ are held in individual pages. It allocates the number of pages it takes
>  to fulfill the request. If more entries may fit on the last page
>  then they will be added.
>
> - # echo 1 > /debug/tracing/trace_entries
> - # cat /debug/tracing/trace_entries
> + # echo 1 > /debug/tracing/buffer_size
> + # cat /debug/tracing/buffer_size
>  85
>
>  This shows us that 85 entries can fit in a single page.
> @@ -1332,8 +1332,8 @@ This shows us that 85 entries can fit in a single page.
>  The number of pages which will be allocated is limited to a percentage
>  of available memory. Allocating too much will produce an error.
>
> - # echo 1000000000000 > /debug/tracing/trace_entries
> + # echo 1000000000000 > /debug/tracing/buffer_size
>  -bash: echo: write error: Cannot allocate memory
> - # cat /debug/tracing/trace_entries
> + # cat /debug/tracing/buffer_size
>  85
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 4bf070b..c681778 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -3198,11 +3198,11 @@ static __init int tracer_init_debugfs(void)
>                pr_warning("Could not create debugfs "
>                           "'trace_pipe' entry\n");
>
> -       entry = debugfs_create_file("trace_entries", 0644, d_tracer,
> +       entry = debugfs_create_file("buffer_size", 0644, d_tracer,
>                                    &global_trace, &tracing_entries_fops);
>        if (!entry)
>                pr_warning("Could not create debugfs "
> -                          "'trace_entries' entry\n");
> +                          "'buffer_size' entry\n");
>
>        entry = debugfs_create_file("trace_marker", 0220, d_tracer,
>                                    NULL, &tracing_mark_fops);
> --
> 1.5.6.5
>
> --
>



Yes this name is much more obvious.
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