[PATCH] user: Document event recording
Gedare Bloom
gedare at rtems.org
Sat Apr 11 13:59:41 UTC 2020
Looks great, please push it. Thanks for this.
On Sat, Apr 11, 2020 at 7:42 AM Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
>
> Close #3904.
> ---
> user/tracing/eventrecording.rst | 222 ++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 212 insertions(+), 10 deletions(-)
>
> diff --git a/user/tracing/eventrecording.rst b/user/tracing/eventrecording.rst
> index d799774..27e929c 100644
> --- a/user/tracing/eventrecording.rst
> +++ b/user/tracing/eventrecording.rst
> @@ -1,6 +1,6 @@
> .. SPDX-License-Identifier: CC-BY-SA-4.0
>
> -.. Copyright (C) 2019 embedded brains GmbH
> +.. Copyright (C) 2019, 2020 embedded brains GmbH
> .. Copyright (C) 2019 Sebastian Huber
>
> .. _EventRecording:
> @@ -35,12 +35,26 @@ operations. The CPU counter is used to get the time of events. It is combined
> with periodic uptime events to synchronize it with the monotonic system clock
> (:c:macro:`CLOCK_MONOTONIC`).
>
> -The application must configure the event recording via the configuration options
> -:c:macro:`CONFIGURE_RECORD_PER_PROCESSOR_ITEMS` and
> -:c:macro:`CONFIGURE_RECORD_EXTENSIONS_ENABLED`.
> +To use the event recording three things come into play. Firstly, there is the
> +generation of event records on the target system (the application running with
> +RTEMS). Secondly, means to transfer the recorded events to the host computer
> +for analysis. Thirdly, the analysis of the recorded events on the host
> +computer.
>
> -Events can be recorded for example with the :c:func:`rtems_record_produce`
> -function.
> +Target System: Configuration and Event Generation
> +-------------------------------------------------
> +
> +The application enables the event recording support via the configuration
> +option :c:macro:`CONFIGURE_RECORD_PER_PROCESSOR_ITEMS`. The configuration
> +option :c:macro:`CONFIGURE_RECORD_EXTENSIONS_ENABLED` enables the generation of
> +thread create, start, restart, delete, switch, begin, exitted and terminate
> +events. Dumps of the event records in a fatal error handler can be enabled by
> +the mutually exclusive :c:macro:`CONFIGURE_RECORD_FATAL_DUMP_BASE64` and
> +:c:macro:`CONFIGURE_RECORD_FATAL_DUMP_BASE64_ZLIB` configuration options.
> +
> +Custom events can be recorded for example with the
> +:c:func:`rtems_record_produce`, :c:func:`rtems_record_line`,
> +:c:func:`rtems_record_caller`, etc. functions.
>
> .. code-block:: c
>
> @@ -49,10 +63,198 @@ function.
> void f( void )
> {
> rtems_record_produce( RTEMS_RECORD_USER( 0 ), 123 );
> + rtems_record_line();
> + rtems_record_caller();
> }
>
> -Recorded events can be sent to a host computer with a very simple record server
> -started by :c:func:`rtems_record_start_server` via a TCP connection.
> +The variants of :c:func:`rtems_record_line` and :c:func:`rtems_record_caller`
> +can be used to easily generate control flow events in the area of interest.
> +The :file:`rtems-record-lttng` tool can use these events to associate source
> +code files and line numbers to them using the ELF file of the application.
> +
> +The following code can be used together with the GCC option
> +``-finstrument-functions`` to generate function entry/exit events for
> +instrumented functions:
> +
> +.. code-block:: c
> +
> + __attribute__(( __no_instrument_function__ ))
> + void __cyg_profile_func_enter( void *this_fn, void *call_site )
> + {
> + rtems_record_produce_2(
> + RTEMS_RECORD_CALLER,
> + (rtems_record_data) call_site,
> + RTEMS_RECORD_FUNCTION_ENTRY,
> + (rtems_record_data) this_fn
> + );
> + }
> +
> + __attribute__(( __no_instrument_function__ ))
> + void __cyg_profile_func_exit( void *this_fn, void *call_site )
> + {
> + rtems_record_produce(
> + RTEMS_RECORD_FUNCTION_EXIT,
> + (rtems_record_data) this_fn
> + );
> + }
> +
> +To generate interrupt handler entry/exit events, the following patch can be
> +used:
> +
> +.. code-block:: diff
> +
> + diff --git a/bsps/arm/shared/clock/clock-armv7m.c b/bsps/arm/shared/clock/clock-armv7m.c
> + index 255de1ca42..0d37c63ac6 100644
> + --- a/bsps/arm/shared/clock/clock-armv7m.c
> + +++ b/bsps/arm/shared/clock/clock-armv7m.c
> + @@ -29,6 +29,7 @@
> + #include <bsp/clock-armv7m.h>
> +
> + #include <rtems.h>
> + +#include <rtems/record.h>
> + #include <rtems/sysinit.h>
> +
> + #ifdef ARM_MULTILIB_ARCH_V7M
> + @@ -45,9 +46,11 @@ static uint32_t _ARMV7M_TC_get_timecount(struct timecounter *base)
> +
> + void _ARMV7M_Clock_handler(void)
> + {
> + + rtems_record_produce(RTEMS_RECORD_INTERRUPT_ENTRY, ARMV7M_VECTOR_SYSTICK);
> + _ARMV7M_Interrupt_service_enter();
> + Clock_isr(NULL);
> + _ARMV7M_Interrupt_service_leave();
> + + rtems_record_produce(RTEMS_RECORD_INTERRUPT_EXIT, ARMV7M_VECTOR_SYSTICK);
> + }
> +
> + static void _ARMV7M_Clock_handler_install(void)
> + diff --git a/bsps/include/bsp/irq-generic.h b/bsps/include/bsp/irq-generic.h
> + index 31835d07ba..2ab2f78b65 100644
> + --- a/bsps/include/bsp/irq-generic.h
> + +++ b/bsps/include/bsp/irq-generic.h
> + @@ -30,6 +30,7 @@
> + #include <stdbool.h>
> +
> + #include <rtems/irq-extension.h>
> + +#include <rtems/record.h>
> + #include <rtems/score/assert.h>
> +
> + #ifdef RTEMS_SMP
> + @@ -258,6 +259,7 @@ void bsp_interrupt_vector_disable(rtems_vector_number vector);
> + */
> + static inline void bsp_interrupt_handler_dispatch(rtems_vector_number vector)
> + {
> + + rtems_record_produce(RTEMS_RECORD_INTERRUPT_ENTRY, vector);
> + if (bsp_interrupt_is_valid_vector(vector)) {
> + const bsp_interrupt_handler_entry *e =
> + &bsp_interrupt_handler_table [bsp_interrupt_handler_index(vector)];
> + @@ -276,6 +278,7 @@ static inline void bsp_interrupt_handler_dispatch(rtems_vector_number vector)
> + } else {
> + bsp_interrupt_handler_default(vector);
> + }
> + + rtems_record_produce(RTEMS_RECORD_INTERRUPT_EXIT, vector);
> + }
> +
> + /**
> +
> +Transfer of Event Records to the Host Computer
> +----------------------------------------------
> +
> +Recorded events can be sent to a host computer with a record server started by
> +:c:func:`rtems_record_start_server` via a TCP connection.
> +
> +In the fatal error handler, the event records can be dumped via
> +:c:func:`rtems_putc` in Base64 encoding. Optionally, the event records can be
> +compressed via zlib before they are dumped in Base64 encoding. The compression
> +needs roughly 512KiB of statically allocated memory.
> +
> +Analysis of Event Records on the Host Computer
> +----------------------------------------------
> +
> +Use the command line tool :file:`rtems-record-lttng` to get recorded events
> +from the record server running on the target system or from a file to convert
> +the event records into CTF. It can be also used to read the dumps in Base64
> +encoding generated by the fatal error handler. The tool outputs the event
> +records in the `Common Trace Format (CTF) <https://diamon.org/ctf/>`_ with some
> +extra support for the
> +`Linux Trace Toolkit Next Generation (LTTng) <https://lttng.org/>`_. This
> +format can be analysed using `babeltrace <https://babeltrace.org/>`_ or
> +`Eclipse Trace Compass <https://www.eclipse.org/tracecompass/>`_.
> +
> +For example, to get the event records from the record server running on the
> +target use:
> +
> +.. code-block:: none
> +
> + mkdir new-trace
> + cd new-trace
> + rtems-record-lttng -e application.exe -H 192.168.188.84 -l 100000
> +
> +If everything is set up correctly, then the command produces a :file:`metadata`
> +file and one stream file :file:`stream_0`, etc. for each processor which
> +generated event records.
> +
> +.. code-block:: none
> +
> + $ ls -l
> + total 120
> + -rw-r--r-- 1 user group 108339 Apr 11 15:28 metadata
> + -rw-r--r-- 1 user group 8701 Apr 11 15:28 stream_0
> +
> +This output in CTF can be used by :file:`babeltrace` and
> +`Eclipse Trace Compass` for further analysis, for example:
> +
> +.. code-block:: none
> +
> + $ babeltrace .
> + [07:28:15.909340000] (+?.?????????) RTEMS THREAD_STACK_CURRENT: { cpu_id = 0 }, { data = 0xB10 }
> + [07:28:15.909340000] (+0.000000000) RTEMS sched_switch: { cpu_id = 0 }, { prev_comm = "UI1 ", prev_tid = 167837697, prev_prio = 0, prev_state = 0, next_comm = "IDLE/0", next_tid = 0, next_prio = 0 }
> + [07:28:15.909519999] (+0.000179999) RTEMS THREAD_STACK_CURRENT: { cpu_id = 0 }, { data = 0xD68 }
> + [07:28:15.909519999] (+0.000000000) RTEMS sched_switch: { cpu_id = 0 }, { prev_comm = "IDLE/0", prev_tid = 0, prev_prio = 0, prev_state = 1026, next_comm = "UI1 ", next_tid = 167837697, next_prio = 0 }
> + [07:28:15.909579999] (+0.000060000) RTEMS THREAD_STACK_CURRENT: { cpu_id = 0 }, { data = 0xB10 }
> + ...
> + [07:28:15.999940999] (+0.000000000) RTEMS USER_4: { cpu_id = 0 }, { data = 0x4000192C }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_0: { cpu_id = 0 }, { data = 0x0 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_1: { cpu_id = 0 }, { data = 0x1 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_2: { cpu_id = 0 }, { data = 0x2 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_3: { cpu_id = 0 }, { data = 0x3 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_4: { cpu_id = 0 }, { data = 0x4 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_5: { cpu_id = 0 }, { data = 0x5 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_6: { cpu_id = 0 }, { data = 0x6 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_7: { cpu_id = 0 }, { data = 0x7 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_8: { cpu_id = 0 }, { data = 0x8 }
> + [07:28:15.999940999] (+0.000000000) RTEMS RETURN_9: { cpu_id = 0 }, { data = 0x9 }
> + [07:28:15.999940999] (+0.000000000) RTEMS ISR_DISABLE: { cpu_id = 0 }, { code = "generate_events at init.c:154" }
> + [07:28:15.999940999] (+0.000000000) RTEMS ISR_ENABLE: { cpu_id = 0 }, { code = "Init at init.c:181" }
> +
> +A dump from the fatal error handler looks like this:
> +
> +.. code-block:: none
> +
> + *** BEGIN OF RECORDS BASE64 ZLIB ***
> + eNqtlE1vE1cUhsdJWgg0jU2GABILpxUVkaJcTxzH8QqThKpRKTIJlcoyeIKIhGCCEFnAAtAoKgXa
> + phqx6gKk/AAXWHTpTMYZlg0rdpBdF7Dvsuec91jYFEo+HOnq0b33Oe/9mOtks9ns7Y1TK5ZlJah1
> + Uluw8HfJstqYA1b3WJG4a+p4aZpJbZzaXOlrw+4cte+p2Zcuz15kUstS3FhmZGiWOTs6nGM65Xye
> + 6TqZEeZQNnOOWZh1y8KZfEHG3ewMszyE+XJ2hHNyg7lBrs9lhtIZpuMUHObR9LDwuxNnppgDufQ0
> + c2x6Ko35nLBcKOSEeXeYOXM+P8o8lR7oZ85dXJB1HDfN6+aGnbx4/YUR3t/+zgTfUaL3xMmJSe7v
> + 0X7ameTzX9N7m6d7WyNetqyOI93HVgx7xKOWtTdJHOSc7rElo6TxrgvEQfHGbxkl/PFb8F/2GSX8
> + l33wX6WMEv6rlPjJ638YpfhE8ZM3Hhml+ETxUwdOG6X4RPFTB48bpfhE+E82jBL+kw34T9eNEv7T
> + dfH3leaNUnyi+PtOzxil+ET4r1NGCf91Cv6bhFHCf5MQv+fHR0YpPlH8njtLRik+UXz7iGOU4hPF
> + t7/qM0rxifCr60YJv7oOv/rX2aLVk1QetqvP5RFoP0N9/l2R95x/TG32SsTjo8Td4qE/0dDvFB/j
> + Z94zvqch58L/zO8ltqt3cxPeZ8QO9X/fgt9F/ETrqtuo+5z4qdb/vYP6bv7fZIcVyrFtInLCCnLC
> + CnLCCnLCCnLCCnLCCnLCSj0nSdytecUW5qX4/yyxt2gdGtD8b97p/2CHjy1dr3Hco3G8p/Bxm67f
> + OH+jYZ+N4/fes//G+YcfPN/qMrzVZfb+JMJbXYa3ulz3cA/N/otN+Li35rp/tlCH+26q3394G/X4
> + Xs05EzvIwXdvzvNakId3FAXIjQLOfUhEbhQgNwqQGwXIjQLkRgFyowC5UYDcKKjn4n1GD9qRX2c9
> + /91+fb0Pjdf38bH5+j436+l5aovwaz78mg+/5sOv+fBrvvo+zr/tOh/3tuN6H/feshwf36/leT7e
> + Q22xQ3LXrii9O5L/to/11jys9x/P+wnj3l3Zx0fnvXuyz0173n05z5Z972c5/7brvF/k3nZc7/0q
> + 9x6fR07sIid2kRO7yIld5MQucmIXObGLnNjVHHdJvl/L89zf5D3E7rdF6+BV4knJf1b6Uuqelb7g
> + df4FFmd4DQ==
> + *** END OF RECORDS BASE64 ZLIB ***
> +
> +Copy everything between the ``*** BEGIN OF RECORDS BASE64 ZLIB ***`` and the
> +``*** END OF RECORDS BASE64 ZLIB ***`` markers into a file, for example
> +:file:`dump.txt`. Use this command to convert the event records into the CTF
> +for further analysis:
> +
> +.. code-block:: none
>
> -On the host computer you may use the command line tool :file:`rtems-record` to
> -get recorded events from the record server running on the target system.
> + rtems-record-lttng -e application.exe -b -z dump.txt
> --
> 2.16.4
>
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