diff mbox series

[V4,3/3] kernel-shark: Add plugin for handling Xenomai cobalt_context_switch

Message ID 20220110042518.9376-3-hongzhan.chen@intel.com (mailing list archive)
State Changes Requested
Headers show
Series [V4,1/3] kernel-shark: fix typo in sched_events.h | expand

Commit Message

Hongzhan Chen Jan. 10, 2022, 4:25 a.m. UTC
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.chen@intel.com>

Comments

Yordan Karadzhov Jan. 10, 2022, 1:21 p.m. UTC | #1
On 10.01.22 г. 6:25 ч., Hongzhan Chen wrote:
> +	eventFieldIntervalPlot(argvCpp,
> +			       plugin_ctx->cs_data, checkFieldCS,
> +			       plugin_ctx->cs_data, checkEntryPid,
> +			       makeLatencyBox<XenomaiSwitchBox>,
> +			       {0, 0, KS_COBALT_BLUE}, // Cobalt Blue
> +			       -1);         // Default size

Hi Hongzhan,

I meant something different with my comment about 'cobalt blue'. Here you define the color with RGB coordinates (0, 0, 
255). This means 255 on the blue axis and zeros on the red and green. This is what I meant by 'just blue'. The RGB 
coordinates of the 'cobalt blue' color are (0, 71, 171). This means it is some mixture between green and blue.

Cheers,
Yordan
diff mbox series

Patch

diff --git a/src/plugins/CMakeLists.txt b/src/plugins/CMakeLists.txt
index 3e170fa..16f080b 100644
--- a/src/plugins/CMakeLists.txt
+++ b/src/plugins/CMakeLists.txt
@@ -44,6 +44,10 @@  if (Qt5Widgets_FOUND AND TT_FONT_FILE)
                      SOURCE sched_events.c SchedEvents.cpp)
     list(APPEND PLUGIN_LIST "sched_events")
 
+    BUILD_GUI_PLUGIN(NAME xenomai_cobalt_switch_events
+                     SOURCE xenomai_cobalt_switch_events.c CobaltSwitchEvents.cpp)
+    list(APPEND PLUGIN_LIST "xenomai_cobalt_switch_events")
+
     BUILD_GUI_PLUGIN(NAME event_field_plot
                      MOC EventFieldDialog.hpp
                      SOURCE event_field_plot.c EventFieldDialog.cpp EventFieldPlot.cpp)
diff --git a/src/plugins/CobaltSwitchEvents.cpp b/src/plugins/CobaltSwitchEvents.cpp
new file mode 100644
index 0000000..b63399c
--- /dev/null
+++ b/src/plugins/CobaltSwitchEvents.cpp
@@ -0,0 +1,156 @@ 
+// SPDX-License-Identifier: LGPL-2.1
+
+/*
+ * Copyright (C) 2021 Intel Inc, Hongzhan Chen <hongzhan.chen@intel.com>
+ */
+
+/**
+ *  @file    CobaltSwitchEvents.cpp
+ *  @brief   Defines a callback function for Xenomai Cobalt context switch
+ *           events used to plot in blue the out-of-band state of the task
+ */
+
+// KernelShark
+#include "libkshark.h"
+#include "libkshark-plugin.h"
+#include "plugins/xenomai_cobalt_switch_events.h"
+#include "KsPlotTools.hpp"
+#include "KsPlugins.hpp"
+#include "KsMainWindow.hpp"
+
+static KsMainWindow *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 = static_cast<KsMainWindow *>(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
+	{
+		ks4xenomai_ptr->markEntry(_data[1]->entry, DualMarkerState::B);
+		ks4xenomai_ptr->markEntry(_data[0]->entry, DualMarkerState::A);
+	}
+
+};
+
+/*
+ * 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, 0, KS_COBALT_BLUE}, // Cobalt Blue
+			       -1);         // Default size
+}
diff --git a/src/plugins/xenomai_cobalt_switch_events.c b/src/plugins/xenomai_cobalt_switch_events.c
new file mode 100644
index 0000000..f285552
--- /dev/null
+++ b/src/plugins/xenomai_cobalt_switch_events.c
@@ -0,0 +1,174 @@ 
+// SPDX-License-Identifier: LGPL-2.1
+
+/*
+ * Copyright (C) 2021 Intel Inc, Hongzhan Chen <hongzhan.chen@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 "plugins/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;
+	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/src/plugins/xenomai_cobalt_switch_events.h b/src/plugins/xenomai_cobalt_switch_events.h
new file mode 100644
index 0000000..50605fc
--- /dev/null
+++ b/src/plugins/xenomai_cobalt_switch_events.h
@@ -0,0 +1,58 @@ 
+/* SPDX-License-Identifier: LGPL-2.1 */
+
+/*
+ * Copyright (C) 2021 Intel Inc, Hongzhan Chen<hongzhan.chen@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
+
+#define SWITCH_INBAND_STATE	1
+#define KS_COBALT_BLUE		255
+
+/** 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