[PATCH 1/2] kernel-shark: Hide CPUs with no data in them

[PATCH 1/2] kernel-shark: Hide CPUs with no data in them

[Yordan Karadzhov (VMware)]

A hash table, storring all idle CPUs is added to the session context.
If a CPU does not contain any data (is idle), its plot is not shown
by default when KernelShark starts. Note that, if the option '--cpu'
is used, it has priority and if idle CPUs are selected, the
corresponding empty CPU plots will be displayed.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215677
Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 src/KsGLWidget.cpp      | 11 ++++++++---
 src/libkshark-tepdata.c |  5 ++++-
 src/libkshark.c         |  6 ++++++
 src/libkshark.h         |  3 +++
 4 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/src/KsGLWidget.cpp b/src/KsGLWidget.cpp
index 3b2e0d4..1c71ecb 100644
--- a/src/KsGLWidget.cpp
+++ b/src/KsGLWidget.cpp
@@ -419,6 +419,7 @@ void KsGLWidget::keyReleaseEvent(QKeyEvent *event)
 
 void KsGLWidget::_defaultPlots(kshark_context *kshark_ctx)
 {
+	struct kshark_data_stream *stream;
 	QVector<int> streamIds, plotVec;
 	uint64_t tMin, tMax;
 	int nCPUs, nBins;
@@ -432,15 +433,19 @@ void KsGLWidget::_defaultPlots(kshark_context *kshark_ctx)
 	 */
 	streamIds = KsUtils::getStreamIdList(kshark_ctx);
 	for (auto const &sd: streamIds) {
-		nCPUs = kshark_ctx->stream[sd]->n_cpus;
+		stream = kshark_ctx->stream[sd];
+		nCPUs = stream->n_cpus;
 		plotVec.clear();
 
 		/* If the number of CPUs is too big show only the first 16. */
 		if (nCPUs > KS_MAX_START_PLOTS / kshark_ctx->n_streams)
 			nCPUs = KS_MAX_START_PLOTS / kshark_ctx->n_streams;
 
-		for (int i = 0; i < nCPUs; ++i)
-			plotVec.append(i);
+		for (int cpu{0}; cpu < stream->n_cpus && plotVec.count() < nCPUs; ++cpu) {
+			/* Do not add plots for idle CPUs. */
+			if (!kshark_hash_id_find(stream->idle_cpus, cpu))
+				plotVec.append(cpu);
+		}
 
 		_streamPlots[sd]._cpuList = plotVec;
 		_streamPlots[sd]._taskList = {};
diff --git a/src/libkshark-tepdata.c b/src/libkshark-tepdata.c
index 9740ed9..e9244b0 100644
--- a/src/libkshark-tepdata.c
+++ b/src/libkshark-tepdata.c
@@ -391,7 +391,10 @@ static ssize_t get_records(struct kshark_context *kshark_ctx,
 			rec = tracecmd_read_data(kshark_get_tep_input(stream), cpu);
 		}
 
-		total += count;
+		if (!count)
+			kshark_hash_id_add(stream->idle_cpus, cpu);
+		else
+			total += count;
 	}
 
 	*rec_list = cpu_list;
diff --git a/src/libkshark.c b/src/libkshark.c
index 1222a81..44e553f 100644
--- a/src/libkshark.c
+++ b/src/libkshark.c
@@ -121,6 +121,8 @@ static void kshark_stream_free(struct kshark_data_stream *stream)
 	if (!stream)
 		return;
 
+	kshark_hash_id_free(stream->idle_cpus);
+
 	kshark_hash_id_free(stream->show_task_filter);
 	kshark_hash_id_free(stream->hide_task_filter);
 
@@ -147,6 +149,8 @@ static struct kshark_data_stream *kshark_stream_alloc()
 	if (!stream)
 		goto fail;
 
+	stream->idle_cpus = kshark_hash_id_alloc(KS_FILTER_HASH_NBITS);
+
 	stream->show_task_filter = kshark_hash_id_alloc(KS_FILTER_HASH_NBITS);
 	stream->hide_task_filter = kshark_hash_id_alloc(KS_FILTER_HASH_NBITS);
 
@@ -433,6 +437,8 @@ static int kshark_stream_close(struct kshark_data_stream *stream)
 	kshark_hash_id_clear(stream->show_cpu_filter);
 	kshark_hash_id_clear(stream->hide_cpu_filter);
 
+	kshark_hash_id_clear(stream->idle_cpus);
+
 	if (kshark_is_tep(stream))
 		return kshark_tep_close_interface(stream);
 
diff --git a/src/libkshark.h b/src/libkshark.h
index 23e3b49..1514f33 100644
--- a/src/libkshark.h
+++ b/src/libkshark.h
@@ -286,6 +286,9 @@ struct kshark_data_stream {
 	/** The number of CPUs presented in this data stream. */
 	int			n_cpus;
 
+	/** Hash table of Idle CPUs. */
+	struct kshark_hash_id	*idle_cpus;
+
 	/**
 	 * The number of distinct event types presented in this data stream.
 	 */
-- 
2.32.0

[PATCH 2/2] kernel-shark: CPU plots dialog ease spotting empty CPUs

[Yordan Karadzhov (VMware)]

The CPU plots dialog will show only the ones with content. A "hide empty"
checkbox is added, that by default is checked. If it is unchecked, then
all the CPUs would show up.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215677
Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 src/KsWidgetsLib.cpp | 26 +++++++++++++++++++++++++-
 src/KsWidgetsLib.hpp |  7 +++++--
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/KsWidgetsLib.cpp b/src/KsWidgetsLib.cpp
index e30bf27..7b3192d 100644
--- a/src/KsWidgetsLib.cpp
+++ b/src/KsWidgetsLib.cpp
@@ -906,12 +906,35 @@ void KsCheckBoxTreeWidget::_verify()
  * @param parent: The parent of this widget.
  */
 KsCPUCheckBoxWidget::KsCPUCheckBoxWidget(kshark_data_stream *stream, QWidget *parent)
-: KsCheckBoxTreeWidget(stream->stream_id, "CPUs", parent)
+: KsCheckBoxTreeWidget(stream->stream_id, "CPUs", parent),
+  _hideEmpty("hide empty")
 {
 	int height(FONT_HEIGHT * 1.5);
 	KsPlot::ColorTable colors;
 	QString style;
 
+	_hideEmpty.setCheckState(Qt::Checked);
+	_tb.addSeparator();
+	_tb.addWidget(&_hideEmpty);
+
+	auto lamHideEmpty = [this, stream] (bool hide) {
+		QTreeWidgetItem *item;
+		bool isIdle;
+
+		for(int cpu = 0; cpu < stream->n_cpus; ++cpu) {
+			item = _tree.topLevelItem(cpu);
+			if (hide) {
+				isIdle = kshark_hash_id_find(stream->idle_cpus, cpu);
+				item->setHidden(isIdle);
+			} else {
+				item->setHidden(false);
+			}
+		}
+	};
+
+	connect(&_hideEmpty,	&QCheckBox::clicked,
+				lamHideEmpty);
+
 	style = QString("QTreeView::item { height: %1 ;}").arg(height);
 	_tree.setStyleSheet(style);
 
@@ -934,6 +957,7 @@ KsCPUCheckBoxWidget::KsCPUCheckBoxWidget(kshark_data_stream *stream, QWidget *pa
 		_cb[i] = cpuItem;
 	}
 
+	lamHideEmpty(true);
 	_adjustSize();
 }
 
diff --git a/src/KsWidgetsLib.hpp b/src/KsWidgetsLib.hpp
index 6ec2bd1..2cc3535 100644
--- a/src/KsWidgetsLib.hpp
+++ b/src/KsWidgetsLib.hpp
@@ -275,10 +275,9 @@ public:
 	/** The user provided an input. The widget has been modified. */
 	bool _userInput;
 
-private:
+protected:
 	QToolBar _tb;
 
-protected:
 	/** Identifier of the Data stream for which the selection applies. */
 	int		_sd;
 
@@ -544,6 +543,10 @@ struct KsCPUCheckBoxWidget : public KsCheckBoxTreeWidget
 
 	KsCPUCheckBoxWidget(kshark_data_stream *stream,
 			    QWidget *parent = nullptr);
+
+private:
+	/** The "hide empty" checkbox. */
+	QCheckBox	_hideEmpty;
 };
 
 /**
-- 
2.32.0

Re: [PATCH 2/2] kernel-shark: CPU plots dialog ease spotting empty CPUs

[Steven Rostedt]

On Wed, 16 Mar 2022 16:37:17 +0200
"Yordan Karadzhov (VMware)" <y.karadz@gmail.com> wrote:

> The CPU plots dialog will show only the ones with content. A "hide empty"
> checkbox is added, that by default is checked. If it is unchecked, then
> all the CPUs would show up.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215677
> Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
> ---
>

This is awesome Yordan!

It's exactly what I was looking for.

Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Although, I found that if I select more that 16 CPU plots at a time it
hangs. I can add that to the BZ. (I noticed this before these patches).

-- Steve

Re: [PATCH 2/2] kernel-shark: CPU plots dialog ease spotting empty CPUs

[Steven Rostedt]

On Wed, 16 Mar 2022 11:03:56 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> Although, I found that if I select more that 16 CPU plots at a time it
> hangs. I can add that to the BZ. (I noticed this before these patches).

Strange, it hung just before posting this, but trying it again, I can't
reproduce the lockup :-/

I'll play some more with it.

-- Steve