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ftrace: rename trace_entries to buffer_size_kb
Impact: rename of debugfs file trace_entries to buffer_size_kb 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_kb" (thanks to Arjan van de Ven for this idea). [ mingo@elte.hu: changed from buffer_size to buffer_size_kb ] ( Note, the units are still bytes - the next patch changes that, to keep the wide rename patch separate from the unit-change patch. ) Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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2 changed files with 11 additions and 11 deletions
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@ -94,7 +94,7 @@ of ftrace. Here is a list of some of the key files:
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only be recorded if the latency is greater than
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the value in this file. (in microseconds)
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trace_entries: This sets or displays the number of bytes each CPU
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buffer_size_kb: This sets or displays the number of bytes each CPU
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buffer can hold. The tracer buffers are the same size
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for each CPU. The displayed number is the size of the
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CPU buffer and not total size of all buffers. The
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@ -1299,13 +1299,13 @@ trace entries
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-------------
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Having too much or not enough data can be troublesome in diagnosing
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an issue in the kernel. The file trace_entries is used to modify
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an issue in the kernel. The file buffer_size_kb is used to modify
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the size of the internal trace buffers. The number listed
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is the number of entries that can be recorded per CPU. To know
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the full size, multiply the number of possible CPUS with the
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number of entries.
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# cat /debug/tracing/trace_entries
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# cat /debug/tracing/buffer_size_kb
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65620
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Note, to modify this, you must have tracing completely disabled. To do that,
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@ -1313,8 +1313,8 @@ echo "nop" into the current_tracer. If the current_tracer is not set
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to "nop", an EINVAL error will be returned.
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# echo nop > /debug/tracing/current_tracer
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# echo 100000 > /debug/tracing/trace_entries
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# cat /debug/tracing/trace_entries
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# echo 100000 > /debug/tracing/buffer_size_kb
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# cat /debug/tracing/buffer_size_kb
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100045
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@ -1323,8 +1323,8 @@ are held in individual pages. It allocates the number of pages it takes
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to fulfill the request. If more entries may fit on the last page
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then they will be added.
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# echo 1 > /debug/tracing/trace_entries
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# cat /debug/tracing/trace_entries
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# echo 1 > /debug/tracing/buffer_size_kb
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# cat /debug/tracing/buffer_size_kb
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85
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This shows us that 85 entries can fit in a single page.
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@ -1332,8 +1332,8 @@ This shows us that 85 entries can fit in a single page.
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The number of pages which will be allocated is limited to a percentage
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of available memory. Allocating too much will produce an error.
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# echo 1000000000000 > /debug/tracing/trace_entries
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# echo 1000000000000 > /debug/tracing/buffer_size_kb
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-bash: echo: write error: Cannot allocate memory
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# cat /debug/tracing/trace_entries
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# cat /debug/tracing/buffer_size_kb
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85
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@ -3198,11 +3198,11 @@ static __init int tracer_init_debugfs(void)
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pr_warning("Could not create debugfs "
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"'trace_pipe' entry\n");
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entry = debugfs_create_file("trace_entries", 0644, d_tracer,
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entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer,
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&global_trace, &tracing_entries_fops);
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if (!entry)
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pr_warning("Could not create debugfs "
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"'trace_entries' entry\n");
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"'buffer_size_kb' entry\n");
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entry = debugfs_create_file("trace_marker", 0220, d_tracer,
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NULL, &tracing_mark_fops);
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