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doc: move README.trace to HTML documentation
Convert README.trace to reStructured text and move it to develop/trace.rst. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Heinrich Schuchardt
@@ -12,3 +12,4 @@ Develop U-Boot
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crash_dumps
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global_data
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logging
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trace
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@@ -1,6 +1,5 @@
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# SPDX-License-Identifier: GPL-2.0+
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#
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# Copyright (c) 2013 The Chromium OS Authors.
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.. SPDX-License-Identifier: GPL-2.0+
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.. Copyright (c) 2013 The Chromium OS Authors.
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Tracing in U-Boot
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=================
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@@ -33,73 +32,82 @@ this, follow these steps:
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Add the following to include/configs/sandbox.h (if not already there)
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#define CONFIG_TRACE
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#define CONFIG_CMD_TRACE
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#define CONFIG_TRACE_BUFFER_SIZE (16 << 20)
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#define CONFIG_TRACE_EARLY_SIZE (8 << 20)
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#define CONFIG_TRACE_EARLY
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#define CONFIG_TRACE_EARLY_ADDR 0x00100000
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.. code-block:: c
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#define CONFIG_TRACE
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#define CONFIG_CMD_TRACE
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#define CONFIG_TRACE_BUFFER_SIZE (16 << 20)
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#define CONFIG_TRACE_EARLY_SIZE (8 << 20)
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#define CONFIG_TRACE_EARLY
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#define CONFIG_TRACE_EARLY_ADDR 0x00100000
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Build sandbox U-Boot with tracing enabled:
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$ make FTRACE=1 O=sandbox sandbox_config
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$ make FTRACE=1 O=sandbox
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.. code-block:: console
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$ make FTRACE=1 O=sandbox sandbox_config
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$ make FTRACE=1 O=sandbox
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Run sandbox, wait for a bit of trace information to appear, and then capture
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a trace:
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$ ./sandbox/u-boot
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.. code-block:: console
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$ ./sandbox/u-boot
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U-Boot 2013.04-rc2-00100-ga72fcef (Apr 17 2013 - 19:25:24)
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U-Boot 2013.04-rc2-00100-ga72fcef (Apr 17 2013 - 19:25:24)
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DRAM: 128 MiB
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trace: enabled
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Using default environment
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DRAM: 128 MiB
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trace: enabled
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Using default environment
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In: serial
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Out: serial
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Err: serial
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=>trace stats
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671,406 function sites
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69,712 function calls
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0 untracked function calls
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73,373 traced function calls
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16 maximum observed call depth
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15 call depth limit
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66,491 calls not traced due to depth
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=>trace stats
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671,406 function sites
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In: serial
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Out: serial
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Err: serial
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=>trace stats
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671,406 function sites
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69,712 function calls
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0 untracked function calls
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73,373 traced function calls
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16 maximum observed call depth
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15 call depth limit
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66,491 calls not traced due to depth
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=>trace stats
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671,406 function sites
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1,279,450 function calls
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0 untracked function calls
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950,490 traced function calls (333217 dropped due to overflow)
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16 maximum observed call depth
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15 call depth limit
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1,275,767 calls not traced due to depth
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=>trace calls 0 e00000
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Call list dumped to 00000000, size 0xae0a40
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=>print
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baudrate=115200
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profbase=0
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profoffset=ae0a40
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profsize=e00000
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stderr=serial
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stdin=serial
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stdout=serial
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0 untracked function calls
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950,490 traced function calls (333217 dropped due to overflow)
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16 maximum observed call depth
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15 call depth limit
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1,275,767 calls not traced due to depth
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=>trace calls 0 e00000
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Call list dumped to 00000000, size 0xae0a40
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=>print
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baudrate=115200
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profbase=0
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profoffset=ae0a40
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profsize=e00000
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stderr=serial
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stdin=serial
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stdout=serial
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Environment size: 117/8188 bytes
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=>host save host 0 trace 0 ${profoffset}
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11405888 bytes written in 10 ms (1.1 GiB/s)
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=>reset
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Environment size: 117/8188 bytes
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=>host save host 0 trace 0 ${profoffset}
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11405888 bytes written in 10 ms (1.1 GiB/s)
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=>reset
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Then run proftool to convert the trace information to ftrace format.
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Then run proftool to convert the trace information to ftrace format
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$ ./sandbox/tools/proftool -m sandbox/System.map -p trace dump-ftrace >trace.txt
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.. code-block:: console
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Finally run pytimechart to display it:
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$ ./sandbox/tools/proftool -m sandbox/System.map -p trace dump-ftrace >trace.txt
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$ pytimechart trace.txt
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Finally run pytimechart to display it
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.. code-block:: console
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$ pytimechart trace.txt
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Using this tool you can zoom and pan across the trace, with the function
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calls on the left and little marks representing the start and end of each
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@@ -109,31 +117,31 @@ function.
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CONFIG Options
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--------------
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- CONFIG_TRACE
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Enables the trace feature in U-Boot.
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CONFIG_TRACE
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Enables the trace feature in U-Boot.
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- CONFIG_CMD_TRACE
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Enables the trace command.
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CONFIG_CMD_TRACE
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Enables the trace command.
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- CONFIG_TRACE_BUFFER_SIZE
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Size of trace buffer to allocate for U-Boot. This buffer is
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used after relocation, as a place to put function tracing
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information. The address of the buffer is determined by
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the relocation code.
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CONFIG_TRACE_BUFFER_SIZE
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Size of trace buffer to allocate for U-Boot. This buffer is
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used after relocation, as a place to put function tracing
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information. The address of the buffer is determined by
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the relocation code.
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- CONFIG_TRACE_EARLY
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Define this to start tracing early, before relocation.
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CONFIG_TRACE_EARLY
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Define this to start tracing early, before relocation.
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- CONFIG_TRACE_EARLY_SIZE
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Size of 'early' trace buffer. Before U-Boot has relocated
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it doesn't have a proper trace buffer. On many boards
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you can define an area of memory to use for the trace
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buffer until the 'real' trace buffer is available after
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relocation. The contents of this buffer are then copied to
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the real buffer.
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CONFIG_TRACE_EARLY_SIZE
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Size of 'early' trace buffer. Before U-Boot has relocated
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it doesn't have a proper trace buffer. On many boards
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you can define an area of memory to use for the trace
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buffer until the 'real' trace buffer is available after
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relocation. The contents of this buffer are then copied to
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the real buffer.
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- CONFIG_TRACE_EARLY_ADDR
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Address of early trace buffer
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CONFIG_TRACE_EARLY_ADDR
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Address of early trace buffer
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Building U-Boot with Tracing Enabled
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@@ -191,20 +199,20 @@ Commands
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The trace command has variable sub-commands:
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- stats
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Display tracing statistics
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stats
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Display tracing statistics
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- pause
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Pause tracing
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pause
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Pause tracing
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- resume
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Resume tracing
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resume
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Resume tracing
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- funclist [<addr> <size>]
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Dump a list of functions into the buffer
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funclist [<addr> <size>]
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Dump a list of functions into the buffer
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- calls [<addr> <size>]
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Dump function call trace into buffer
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calls [<addr> <size>]
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Dump function call trace into buffer
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If the address and size are not given, these are obtained from environment
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variables (see below). In any case the environment variables are updated
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@@ -216,14 +224,14 @@ Environment Variables
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The following are used:
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- profbase
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Base address of trace output buffer
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profbase
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Base address of trace output buffer
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- profoffset
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Offset of first unwritten byte in trace output buffer
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profoffset
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Offset of first unwritten byte in trace output buffer
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- profsize
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Size of trace output buffer
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profsize
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Size of trace output buffer
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All of these are set by the 'trace calls' command.
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@@ -231,18 +239,18 @@ These variables keep track of the amount of data written to the trace
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output buffer by the 'trace' command. The trace commands which write data
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to the output buffer can use these to specify the buffer to write to, and
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update profoffset each time. This allows successive commands to append data
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to the same buffer, for example:
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to the same buffer, for example::
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trace funclist 10000 e00000
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trace calls
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=> trace funclist 10000 e00000
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=> trace calls
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(the latter command appends more data to the buffer).
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- fakegocmd
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Specifies commands to run just before booting the OS. This
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is a useful time to write the trace data to the host for
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processing.
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fakegocmd
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Specifies commands to run just before booting the OS. This
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is a useful time to write the trace data to the host for
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processing.
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Writing Out Trace Data
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@@ -250,11 +258,11 @@ Writing Out Trace Data
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Once the trace data is in an output buffer in memory there are various ways
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to transmit it to the host. Notably you can use tftput to send the data
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over a network link:
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over a network link::
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fakegocmd=trace pause; usb start; set autoload n; bootp;
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trace calls 10000000 1000000;
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tftpput ${profbase} ${profoffset} 192.168.1.4:/tftpboot/calls
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fakegocmd=trace pause; usb start; set autoload n; bootp;
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trace calls 10000000 1000000;
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tftpput ${profbase} ${profoffset} 192.168.1.4:/tftpboot/calls
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This starts up USB (to talk to an attached USB Ethernet dongle), writes
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a trace log to address 10000000 and sends it to a host machine using
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@@ -272,16 +280,17 @@ This tool must be given the U-Boot map file and the trace data received
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from running that U-Boot. It produces a text output file.
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Options
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-m <map_file>
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Specify U-Boot map file
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-p <trace_file>
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Specifiy profile/trace file
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-m <map_file>
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Specify U-Boot map file
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-p <trace_file>
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Specifiy profile/trace file
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Commands:
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- dump-ftrace
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Write a text dump of the file in Linux ftrace format to stdout
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dump-ftrace
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Write a text dump of the file in Linux ftrace format to stdout
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Viewing the Trace Data
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@@ -301,17 +310,17 @@ The following suggestions may be helpful if you are trying to reduce boot
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time:
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1. Enable CONFIG_BOOTSTAGE and CONFIG_BOOTSTAGE_REPORT. This should get
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you are helpful overall snapshot of the boot time.
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you are helpful overall snapshot of the boot time.
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2. Build U-Boot with tracing and run it. Note the difference in boot time
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(it is common for tracing to add 10% to the time)
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(it is common for tracing to add 10% to the time)
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3. Collect the trace information as descibed above. Use this to find where
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all the time is being spent.
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all the time is being spent.
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4. Take a look at that code and see if you can optimise it. Perhaps it is
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possible to speed up the initialisation of a device, or remove an unused
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feature.
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possible to speed up the initialisation of a device, or remove an unused
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feature.
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5. Rebuild, run and collect again. Compare your results.
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