For Xenomai-cobalt enabled system, cobalt_switch_context means
that there is schedule and context switch in companion core(realtime
core), which we may need to do special treatment and take correct
action as main kernel sched_switch to visualize out-of-band state
of realtime tasks running in cobalt core. To achive our target,
we implement following:
1. store corresponding cobalt_switch_context events into
container data.
2. modify pid stored in entry to be equal to next_pid to
show correct color in cpu bar when cobalt_switch_context
event happen.
3. show blue hollow box to mark out-of-band state according to
cobalt_switch_context events.
4. clickable cobalt_switch_context plugin shapes.
Signed-off-by: Hongzhan Chen <hongzhan.c...@intel.com>
---
tracing/Makefile.am | 6 +
tracing/kernelshark/CobaltSwitchEvents.cpp | 156 ++++++++++++++++
tracing/kernelshark/Makefile.am | 18 ++
tracing/kernelshark/README | 75 ++++++++
.../xenomai_cobalt_switch_events.c | 174 ++++++++++++++++++
.../xenomai_cobalt_switch_events.h | 58 ++++++
6 files changed, 487 insertions(+)
create mode 100644 tracing/Makefile.am
create mode 100644 tracing/kernelshark/CobaltSwitchEvents.cpp
create mode 100644 tracing/kernelshark/Makefile.am
create mode 100644 tracing/kernelshark/README
create mode 100644 tracing/kernelshark/xenomai_cobalt_switch_events.c
create mode 100644 tracing/kernelshark/xenomai_cobalt_switch_events.h
diff --git a/tracing/Makefile.am b/tracing/Makefile.am
new file mode 100644
index 000000000..8bdf1f906
--- /dev/null
+++ b/tracing/Makefile.am
@@ -0,0 +1,6 @@
+
+SUBDIRS = \
+ kernelshark
+
+DIST_SUBDIRS = \
+ kernelshark
diff --git a/tracing/kernelshark/CobaltSwitchEvents.cpp
b/tracing/kernelshark/CobaltSwitchEvents.cpp
new file mode 100644
index 000000000..3a521bdfc
--- /dev/null
+++ b/tracing/kernelshark/CobaltSwitchEvents.cpp
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+/*
+ * Copyright (C) 2021 Intel Inc, Hongzhan Chen <hongzhan.c...@intel.com>
+ */
+
+/**
+ * @file CobaltSwitchEvents.cpp
+ * @brief Defines a callback function for Xenomai Cobalt context switch
+ * events used to plot in cobalt blue the out-of-band state of
+ * the task
+ */
+
+// KernelShark
+#include "libkshark.h"
+#include "libkshark-plugin.h"
+#include "xenomai_cobalt_switch_events.h"
+#include "KsPlotTools.hpp"
+#include "KsPlugins.hpp"
+#include "KsPluginsGUI.hpp"
+
+static void *ks4xenomai_ptr;
+
+/**
+ * @brief Provide the plugin with a pointer to the KsMainWindow object (the GUI
+ * itself) such that the plugin can manipulate the GUI.
+ */
+__hidden void *plugin_set_gui_ptr(void *gui_ptr)
+{
+ ks4xenomai_ptr = gui_ptr;
+ return nullptr;
+}
+
+/**
+ * This class represents the graphical element visualizing OOB state between
+ * two cobalt_switch_context events.
+ */
+class XenomaiSwitchBox : public LatencyBox
+{
+ /** On double click do. */
+ void _doubleClick() const override
+ {
+ markEntryB(ks4xenomai_ptr, _data[1]->entry);
+ markEntryA(ks4xenomai_ptr, _data[0]->entry);
+ }
+};
+
+/*
+ * Ideally, the cobalt_switch_context has to be the last trace event recorded
before
+ * the task is preempted. Because of this, when the data is loaded (the first
pass),
+ * the "pid" field of the cobalt_switch_context entries gets edited by this
plugin
+ * to be equal to the "next pid" of the cobalt_switch_context event. However,
in
+ * reality the cobalt_switch_context event may be followed by some trailing
events
+ * from the same task (printk events for example). This has the effect of
extending
+ * the graph of the task outside of the actual duration of the task. The
"second
+ * pass" over the data is used to fix this problem. It takes advantage of the
+ * "next" field of the entry (this field is set during the first pass) to
search
+ * for trailing events after the "cobalt_switch_context". In addition, when
+ * we find that it try to switch in-band because next-pid is zero, we prefer to
+ * skip this event because it try to leave oob not enterring.
+ */
+static void secondPass(plugin_cobalt_context *plugin_ctx)
+{
+ kshark_data_container *cSS;
+ kshark_entry *e;
+ int pid_rec, switch_inband;
+
+ cSS = plugin_ctx->cs_data;
+ for (ssize_t i = 0; i < cSS->size; ++i) {
+ switch_inband = plugin_cobalt_check_switch_inband(
+ cSS->data[i]->field);
+
+ /* we skip cobalt_switch_context that try to
+ * switch into in-band state because we just handle
+ * out-of-band
+ */
+ if (switch_inband)
+ continue;
+ pid_rec = plugin_sched_get_pid(cSS->data[i]->field);
+ e = cSS->data[i]->entry;
+ if (!e->next || e->pid == 0 ||
+ e->event_id == e->next->event_id ||
+ pid_rec != e->next->pid)
+ continue;
+
+ e = e->next;
+ /* Find all trailing events. */
+ for (; e->next; e = e->next) {
+ if (e->pid == plugin_sched_get_pid(
+ cSS->data[i]->field)) {
+ /*
+ * Change the "pid" to be equal to the "next
+ * pid" of the cobalt_switch_context event
+ * and leave a sign that you edited this
+ * entry.
+ */
+ e->pid = cSS->data[i]->entry->pid;
+ e->visible &= ~KS_PLUGIN_UNTOUCHED_MASK;
+
+ /* This is the last trailing event, we finish
+ * this round.
+ */
+ if (e->next->pid != plugin_sched_get_pid(
+ cSS->data[i]->field))
+ break;
+ }
+ }
+ }
+}
+
+/**
+ * @brief Plugin's draw function.
+ *
+ * @param argv_c: A C pointer to be converted to KsCppArgV (C++ struct).
+ * @param sd: Data stream identifier.
+ * @param pid: Process Id.
+ * @param draw_action: Draw action identifier.
+ */
+__hidden void plugin_cobalt_draw(kshark_cpp_argv *argv_c,
+ int sd, int pid, int draw_action)
+{
+ plugin_cobalt_context *plugin_ctx;
+
+ if (!(draw_action & KSHARK_TASK_DRAW) || pid == 0)
+ return;
+
+ plugin_ctx = __get_context(sd);
+ if (!plugin_ctx)
+ return;
+
+ KsCppArgV *argvCpp = KS_ARGV_TO_CPP(argv_c);
+
+ if (!plugin_ctx->second_pass_done) {
+ /* The second pass is not done yet. */
+ secondPass(plugin_ctx);
+ plugin_ctx->second_pass_done = true;
+ }
+
+ IsApplicableFunc checkFieldCS = [=] (kshark_data_container *d,
+ ssize_t i) {
+ return !(plugin_cobalt_check_switch_inband(d->data[i]->field))
&&
+ d->data[i]->entry->pid == pid;
+ };
+
+ IsApplicableFunc checkEntryPid = [=] (kshark_data_container *d,
+ ssize_t i) {
+ return plugin_sched_get_pid(d->data[i]->field) == pid;
+ };
+
+ eventFieldIntervalPlot(argvCpp,
+ plugin_ctx->cs_data, checkFieldCS,
+ plugin_ctx->cs_data, checkEntryPid,
+ makeLatencyBox<XenomaiSwitchBox>,
+ {0, 71, 171}, // Cobalt Blue
+ -1); // Default size
+}
diff --git a/tracing/kernelshark/Makefile.am b/tracing/kernelshark/Makefile.am
new file mode 100644
index 000000000..17c4ff217
--- /dev/null
+++ b/tracing/kernelshark/Makefile.am
@@ -0,0 +1,18 @@
+
+lib_LTLIBRARIES = libplugin_xenomai_cobalt_switch_events.la
+
+KS_INCLUDS ?= /usr/local/include/kernelshark
+TRACECMD_INCLUDS ?= /usr/local/include/trace-cmd
+TRACEFS_INCLUDS ?= /usr/local/include/tracefs
+TRACEEVENR_INCLUDS ?= /usr/local/include/traceevent
+
+libplugin_xenomai_cobalt_switch_events_la_SOURCES = \
+ CobaltSwitchEvents.cpp \
+ xenomai_cobalt_switch_events.c \
+ xenomai_cobalt_switch_events.h
+
+libplugin_xenomai_cobalt_switch_events_la_CPPFLAGS = \
+ -I$(KS_INCLUDS) \
+ -I$(TRACECMD_INCLUDS) \
+ -I$(TRACEFS_INCLUDS) \
+ -I$(TRACEEVENR_INCLUDS)
diff --git a/tracing/kernelshark/README b/tracing/kernelshark/README
new file mode 100644
index 000000000..4ed28dd0a
--- /dev/null
+++ b/tracing/kernelshark/README
@@ -0,0 +1,75 @@
+
+What is it?
+=============
+
+ It is Xenomai plugin for KernelShark to visualize out-of-band state
+ of realtime thread running in companion core with making use of
+ cobalt_switch_context events in trace log.
+
+ For more introductions about KernelShark , please refer to [1].
+
+How to build?
+================================
+
+Preparation:
+
+ - compile and install third party softwares that KernelShark depends on:
+ please refer to "Third Party Software" in [2].
+
+ - GIT clone:
+ git clone https://git.kernel.org/pub/scm/utils/trace-cmd/kernel-shark.git
+
+ - build kernel-shark and install both the GUI and libkshark-devel:
+
+ cd kernel-shark/build
+ cmake ../
+ make
+ sudo make install
+
+ Note:
+ Building standlone xenomai plugin based on kernel-shark
+ depends on following patchset after kernelshark-v2.1.0:
+ kernel-shark: Install missing headers (commit
5419186f4bbad68aa16849882a8f12fa9adb22c5)
+ kernel-shark: Add KsPluginsGUI.hpp/.cpp (commit
59b5763c7c52b703e3b8e05be801f7c85365c9d3)
+ kernel-shark: Load 'ctrl' interface for user plugins (commit
e35970770b71f0cc849870512a806dff96bf19e1)
+
+How to use the plugin with KernelShark?
+====================================
+
+ kernelshark -p your_path_of_libplugin_xenomai_cobalt_switch_events.so
your_path_of_trace.dat
+
+What the difference is after Xenomai plug works?
+===============================================
+
+ 1. For those trace log which does not include cobalt_switch_context event,
you may
+ not expect that there is any difference after Xenomai plugin is loaded.
+
+ 2. But when there is cobalt_switch_context event in trace log, the plugin
would
+ try to analysis cobalt_switch_context event and visualize the OOB state
+ with cobalt blue hollow box in the corresponding task bar.
+
+How to check OOB state with cobalt blue hollow box?
+==================================================
+
+ 1. Please check if there is cobalt_switch_context events existing in the log
using
+ search boxes in the list area of kernelshark GUI.
+
+ 2. When there is cobalt_switch_context events existing in the log, please
goto
+ task plots dialog to choose tasks that you may want to check its OOB
state by
+ clicking menu Plots->Tasks and then hit "Apply".
+
+ 3. Selected tasks would be added to the bottom of the graph area as task
plots.
+ You may zoom in to check if there is cobalt blue hollow box showing in
+ the corresponding task bar/plot if the time span is really large and
+ there is too much events.
+
+ 4. When you double click the hollow box, there is two vertical lines
+ that marked as "Mark A" and "Mark B" which you may use to measure time of
+ running in OOB state between two cobalt_switch_context events.
+
+ Note:
+ Please refer to [1] about introduction of search boxes or task plot or
"Mark A" &
+ "Mark B" on Graph Control Area for more detailed info.
+
+[1]: https://kernelshark.org/Documentation.html
+[2]:
https://git.kernel.org/pub/scm/utils/trace-cmd/kernel-shark.git/tree/README
diff --git a/tracing/kernelshark/xenomai_cobalt_switch_events.c
b/tracing/kernelshark/xenomai_cobalt_switch_events.c
new file mode 100644
index 000000000..758966df7
--- /dev/null
+++ b/tracing/kernelshark/xenomai_cobalt_switch_events.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+/*
+ * Copyright (C) 2021 Intel Inc, Hongzhan Chen <hongzhan.c...@intel.com>
+ */
+
+/**
+ * @file xenomai_cobalt_switch_events.c
+ * @brief handle xenomai cobalt switch context event
+ */
+
+// C
+#include <stdlib.h>
+#include <stdio.h>
+
+// trace-cmd
+#include <trace-cmd.h>
+
+// KernelShark
+#include "xenomai_cobalt_switch_events.h"
+#include "libkshark-tepdata.h"
+
+/** Plugin context instance. */
+
+//! @cond Doxygen_Suppress
+
+#define SWITCH_INBAND_SHIFT PREV_STATE_SHIFT
+
+#define SWITCH_INBAND_MASK PREV_STATE_MASK
+
+//! @endcond
+
+static void cobalt_free_context(struct plugin_cobalt_context *plugin_ctx)
+{
+ if (!plugin_ctx)
+ return;
+
+ kshark_free_data_container(plugin_ctx->cs_data);
+}
+
+/* Use the most significant byte to store state marking switch in-band. */
+static void plugin_cobalt_set_switch_inband_state(ks_num_field_t *field,
+ ks_num_field_t inband_state)
+{
+ unsigned long long mask = SWITCH_INBAND_MASK << SWITCH_INBAND_SHIFT;
+ *field &= ~mask;
+ *field |= (inband_state & SWITCH_INBAND_MASK) << SWITCH_INBAND_SHIFT;
+}
+
+/**
+ * @brief Retrieve the state of switch-in-band from the data field stored in
+ * the kshark_data_container object.
+ *
+ * @param field: Input location for the data field.
+ */
+__hidden int plugin_cobalt_check_switch_inband(ks_num_field_t field)
+{
+ unsigned long long mask = SWITCH_INBAND_MASK << SWITCH_INBAND_SHIFT;
+
+ return (field & mask) >> SWITCH_INBAND_SHIFT;
+}
+
+/** A general purpose macro is used to define plugin context. */
+KS_DEFINE_PLUGIN_CONTEXT(struct plugin_cobalt_context, cobalt_free_context);
+
+static bool plugin_cobalt_init_context(struct kshark_data_stream *stream,
+ struct plugin_cobalt_context *plugin_ctx)
+{
+ struct tep_event *event;
+
+ if (!kshark_is_tep(stream))
+ return false;
+
+ plugin_ctx->tep = kshark_get_tep(stream);
+
+ event = tep_find_event_by_name(plugin_ctx->tep,
+ "cobalt_core", "cobalt_switch_context");
+ if (!event)
+ return false;
+
+ plugin_ctx->cobalt_switch_event = event;
+ plugin_ctx->cobalt_switch_next_field =
+ tep_find_any_field(event, "next_pid");
+
+ plugin_ctx->second_pass_done = false;
+
+ plugin_ctx->cs_data = kshark_init_data_container();
+ if (!plugin_ctx->cs_data)
+ return false;
+
+ return true;
+}
+
+static void plugin_cobalt_switch_action(struct kshark_data_stream *stream,
+ void *rec, struct kshark_entry *entry)
+{
+ struct tep_record *record = (struct tep_record *) rec;
+ struct plugin_cobalt_context *plugin_ctx;
+ unsigned long long next_pid;
+ ks_num_field_t ks_field = 0;
+ int ret;
+
+ plugin_ctx = __get_context(stream->stream_id);
+ if (!plugin_ctx)
+ return;
+
+ ret = tep_read_number_field(plugin_ctx->cobalt_switch_next_field,
+ record->data, &next_pid);
+
+ if (ret == 0 && next_pid >= 0) {
+ plugin_sched_set_pid(&ks_field, entry->pid);
+ if (next_pid == 0) {
+ plugin_cobalt_set_switch_inband_state(&ks_field,
+ SWITCH_INBAND_STATE);
+ }
+
+ kshark_data_container_append(plugin_ctx->cs_data,
+ entry, ks_field);
+
+ if (next_pid > 0)
+ entry->pid = next_pid;
+ }
+}
+
+/** Load this plugin. */
+int KSHARK_PLOT_PLUGIN_INITIALIZER(struct kshark_data_stream *stream)
+{
+ struct plugin_cobalt_context *plugin_ctx;
+
+ plugin_ctx = __init(stream->stream_id);
+ if (!plugin_ctx || !plugin_cobalt_init_context(stream, plugin_ctx)) {
+ __close(stream->stream_id);
+ return 0;
+ }
+
+ if (plugin_ctx->cobalt_switch_event) {
+ kshark_register_event_handler(stream,
+
plugin_ctx->cobalt_switch_event->id,
+ plugin_cobalt_switch_action);
+ }
+
+ kshark_register_draw_handler(stream, plugin_cobalt_draw);
+
+ return 1;
+}
+
+/** Unload this plugin. */
+int KSHARK_PLOT_PLUGIN_DEINITIALIZER(struct kshark_data_stream *stream)
+{
+ struct plugin_cobalt_context *plugin_ctx =
__get_context(stream->stream_id);
+ int ret = 0;
+
+ if (plugin_ctx) {
+ if (plugin_ctx->cobalt_switch_event) {
+ kshark_unregister_event_handler(stream,
+
plugin_ctx->cobalt_switch_event->id,
+
plugin_cobalt_switch_action);
+ }
+
+ kshark_unregister_draw_handler(stream, plugin_cobalt_draw);
+
+ ret = 1;
+ }
+
+ __close(stream->stream_id);
+
+ return ret;
+}
+
+/** Initialize the control interface of the plugin. */
+void *KSHARK_MENU_PLUGIN_INITIALIZER(void *gui_ptr)
+{
+ return plugin_set_gui_ptr(gui_ptr);
+}
diff --git a/tracing/kernelshark/xenomai_cobalt_switch_events.h
b/tracing/kernelshark/xenomai_cobalt_switch_events.h
new file mode 100644
index 000000000..f7f4593ff
--- /dev/null
+++ b/tracing/kernelshark/xenomai_cobalt_switch_events.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: LGPL-2.1 */
+
+/*
+ * Copyright (C) 2021 Intel Inc, Hongzhan Chen<hongzhan.c...@intel.com>
+ */
+
+/**
+ * @file xenomai_cobalt_switch_events.h
+ * @brief Plugin for xenomai cobalt switch context event
+ */
+
+#ifndef _KS_PLUGIN_COBALT_SWITCH_H
+#define _KS_PLUGIN_COBALT_SWITCH_H
+
+// KernelShark
+#include "libkshark.h"
+#include "plugins/common_sched.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** cobalt_switch_context is trying to switch in-band. */
+#define SWITCH_INBAND_STATE 1
+
+/** Structure representing a plugin-specific context. */
+struct plugin_cobalt_context {
+ /** Page event used to parse the page. */
+ struct tep_handle *tep;
+
+ /** Pointer to the cobalt_switch_event object. */
+ struct tep_event *cobalt_switch_event;
+
+ /** Pointer to the cobalt_switch_next_field format descriptor. */
+ struct tep_format_field *cobalt_switch_next_field;
+
+ /** True if the second pass is already done. */
+ bool second_pass_done;
+
+ /** Data container for cobalt_switch_context data. */
+ struct kshark_data_container *cs_data;
+
+};
+
+KS_DECLARE_PLUGIN_CONTEXT_METHODS(struct plugin_cobalt_context)
+
+int plugin_cobalt_check_switch_inband(ks_num_field_t field);
+
+void plugin_cobalt_draw(struct kshark_cpp_argv *argv, int sd, int pid,
+ int draw_action);
+
+void *plugin_set_gui_ptr(void *gui_ptr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
--
2.17.1
