[PATCH v4] kernel-shark-2.alpha: Restructure KVMCombo plugin to use CPU mapping information from the trace files

* [PATCH v4] kernel-shark-2.alpha: Restructure KVMCombo plugin to use CPU mapping information from the trace files
@ 2020-04-24  8:54 Tzvetomir Stoyanov (VMware)
  2020-04-27 14:46 ` Yordan Karadzhov (VMware)
  0 siblings, 1 reply; 2+ messages in thread
From: Tzvetomir Stoyanov (VMware) @ 2020-04-24  8:54 UTC (permalink / raw)
  To: rostedt; +Cc: linux-trace-devel

From: Tzvetomir (VMware)  Stoyanov <tz.stoyanov@gmail.com>

In the upcoming trace-cmd 2.9, extra information about host and guest tracing
will be stored in the trace.dat files. Information about host PID - guest vCPU
mapping will be saved in host trace file. This mapping is mandatory for KVMCombo
plugin. Currently, the mapping is extracted for the tracing data.
Getting the information from the trace files is more reliable and solves the use
case with more than one guest.

Signed-off-by: Tzvetomir (VMware)  Stoyanov <tz.stoyanov@gmail.com>
---
 src/libkshark-tepdata.c  | 116 +++++++++++++++++++++++++++++
 src/libkshark-tepdata.h  |  20 +++++
 src/plugins/KVMCombo.cpp | 156 ++++++++++++++++-----------------------
 src/plugins/KVMCombo.hpp |  16 ++--
 4 files changed, 205 insertions(+), 103 deletions(-)

diff --git a/src/libkshark-tepdata.c b/src/libkshark-tepdata.c
index f280e57..c2de817 100644
--- a/src/libkshark-tepdata.c
+++ b/src/libkshark-tepdata.c
@@ -22,6 +22,7 @@
 #include "tracefs/tracefs.h"
 
 // KernelShark
+#include "libkshark.h"
 #include "libkshark-plugin.h"
 #include "libkshark-tepdata.h"
 
@@ -1293,3 +1294,118 @@ char **kshark_tracecmd_local_plugins()
 {
 	return tracefs_tracers(tracefs_get_tracing_dir());
 }
+
+/**
+ * @brief Free an array, allocated by kshark_tracecmd_get_hostguest_mapping() API
+ *
+ *
+ * @param map: Array, allocated by kshark_tracecmd_get_hostguest_mapping() API
+ * @param count: Number of entries in the array
+ *
+ */
+void kshark_tracecmd_free_hostguest_map(struct kshark_host_guest_map *map, int count)
+{
+	int i;
+
+	if (!map)
+		return;
+	for (i = 0; i < count; i++) {
+		free(map[i].guest_name);
+		free(map[i].cpu_pid);
+		memset(&map[i], 0, sizeof(*map));
+	}
+	free(map);
+}
+
+/**
+ * @brief Get mapping of guest VCPU to host task, running that VCPU.
+ *	  Array of mappings for each guest is allocated and returned
+ *	  in map input parameter.
+ *
+ *
+ * @param map: Returns allocated array of kshark_host_guest_map structures, each
+ *	       one describing VCPUs mapping of one guest.
+ *
+ * @return The number of entries in the *map array, or a negative error code on
+ *	   failure.
+ */
+int kshark_tracecmd_get_hostguest_mapping(struct kshark_host_guest_map **map)
+{
+	struct kshark_host_guest_map *gmap = NULL;
+	struct tracecmd_input *peer_handle = NULL;
+	struct kshark_data_stream *peer_stream;
+	struct tracecmd_input *guest_handle = NULL;
+	struct kshark_data_stream *guest_stream;
+	struct kshark_context *kshark_ctx = NULL;
+	unsigned long long trace_id;
+	const char *name;
+	int vcpu_count;
+	const int *cpu_pid;
+	int *stream_ids;
+	int i, j, k;
+	int count = 0;
+	int ret;
+
+	if (!map || !kshark_instance(&kshark_ctx))
+		return -EFAULT;
+	if (*map)
+		return -EEXIST;
+
+	stream_ids = kshark_all_streams(kshark_ctx);
+	for (i = 0; i < kshark_ctx->n_streams; i++) {
+		guest_stream = kshark_get_data_stream(kshark_ctx, stream_ids[i]);
+		if (!guest_stream || guest_stream->format != KS_TEP_DATA)
+			continue;
+		guest_handle = kshark_get_tep_input(guest_stream);
+		if (!guest_handle)
+			continue;
+		trace_id = tracecmd_get_traceid(guest_handle);
+		if (!trace_id)
+			continue;
+		for (j = 0; j < kshark_ctx->n_streams; j++) {
+			if (stream_ids[i] == stream_ids[j])
+				continue;
+			peer_stream = kshark_get_data_stream(kshark_ctx, stream_ids[j]);
+			if (!peer_stream || peer_stream->format != KS_TEP_DATA)
+				continue;
+			peer_handle = kshark_get_tep_input(peer_stream);
+			if (!peer_handle)
+				continue;
+			ret = tracecmd_get_guest_cpumap(peer_handle, trace_id,
+							&name, &vcpu_count, &cpu_pid);
+			if (!ret && vcpu_count) {
+				gmap = realloc(*map,
+					       (count + 1) * sizeof(struct kshark_host_guest_map));
+				if (!gmap)
+					goto mem_error;
+				*map = gmap;
+				memset(&gmap[count], 0, sizeof(struct kshark_host_guest_map));
+				count++;
+				gmap[count - 1].guest_id = stream_ids[i];
+				gmap[count - 1].host_id = stream_ids[j];
+				gmap[count - 1].guest_name = strdup(name);
+				if (!gmap[count - 1].guest_name)
+					goto mem_error;
+				gmap[count - 1].vcpu_count = vcpu_count;
+				gmap[count - 1].cpu_pid = malloc(sizeof(int) * vcpu_count);
+				if (!gmap[count - 1].cpu_pid)
+					goto mem_error;
+				for (k = 0; k < vcpu_count; k++)
+					gmap[count - 1].cpu_pid[k] = cpu_pid[k];
+				break;
+			}
+		}
+	}
+
+	free(stream_ids);
+	return count;
+
+mem_error:
+	free(stream_ids);
+	if (*map) {
+		kshark_tracecmd_free_hostguest_map(*map, count);
+		*map = NULL;
+	}
+
+	return -ENOMEM;
+}
diff --git a/src/libkshark-tepdata.h b/src/libkshark-tepdata.h
index 53f6aff..0b4b2e2 100644
--- a/src/libkshark-tepdata.h
+++ b/src/libkshark-tepdata.h
@@ -59,6 +59,26 @@ struct tep_record;
 ssize_t kshark_load_tep_records(struct kshark_context *kshark_ctx, int sd,
 				struct tep_record ***data_rows);
 
+struct kshark_host_guest_map {
+	/** ID of guest stream */
+	int guest_id;
+
+	/** ID of host stream */
+	int host_id;
+
+	/** Guest name */
+	char *guest_name;
+
+	/** Number of guest's CPUs in *cpu_pid array */
+	int vcpu_count;
+
+	/** Array of host task PIDs, index is the VCPU id */
+	int *cpu_pid;
+};
+
+void kshark_tracecmd_free_hostguest_map(struct kshark_host_guest_map *map, int count);
+int kshark_tracecmd_get_hostguest_mapping(struct kshark_host_guest_map **map);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/plugins/KVMCombo.cpp b/src/plugins/KVMCombo.cpp
index 1ae03aa..30eac95 100644
--- a/src/plugins/KVMCombo.cpp
+++ b/src/plugins/KVMCombo.cpp
@@ -69,20 +69,30 @@ KsVCPUCheckBoxWidget::KsVCPUCheckBoxWidget(QWidget *parent)
 	_initTree();
 }
 
-void KsVCPUCheckBoxWidget::update(int sdHost, VCPUVector vcpus)
+void KsVCPUCheckBoxWidget::update(int GuestId,
+				  kshark_host_guest_map *gMap, int gMapCount)
 {
-	int nVCPUs = vcpus.count();
 	KsPlot::ColorTable colors;
+	int j;
+
+	for (j = 0; j < gMapCount; j++)
+		if (gMap[j].guest_id == GuestId)
+			break;
+	if (j == gMapCount)
+		return;
 
 	_tree.clear();
-	_id.resize(nVCPUs);
-	_cb.resize(nVCPUs);
+	_id.resize(gMap[j].vcpu_count);
+	_cb.resize(gMap[j].vcpu_count);
 	colors = KsPlot::getCPUColorTable();
 
-	for (int i = 0; i < nVCPUs; ++i) {
+	for (int i = 0; i < gMap[j].vcpu_count; ++i) {
+		QString strCPU = QLatin1String("vCPU ") + QString::number(i);
+		strCPU += (QLatin1String("\t<") + QLatin1String(gMap[j].guest_name) + QLatin1Char('>'));
+
 		QTreeWidgetItem *cpuItem = new QTreeWidgetItem;
 		cpuItem->setText(0, "  ");
-		cpuItem->setText(1, QString("vCPU %1").arg(vcpus.at(i).second));
+		cpuItem->setText(1, strCPU);
 		cpuItem->setCheckState(0, Qt::Checked);
 		cpuItem->setBackgroundColor(0, QColor(colors[i].r(),
 						      colors[i].g(),
@@ -168,26 +178,41 @@ KsComboPlotDialog::KsComboPlotDialog(QWidget *parent)
 		this,			SLOT(_guestStreamChanged(const QString &)));
 
 	setLayout(&_topLayout);
+
+	_guestMapCount = 0;
+	_guestMap = nullptr;
 }
 
-void KsComboPlotDialog::update(int sdHost, VCPUVector vcpus)
+KsComboPlotDialog::~KsComboPlotDialog()
+{
+	kshark_tracecmd_free_hostguest_map(_guestMap, _guestMapCount);
+}
+
+void KsComboPlotDialog::update()
 {
 	kshark_context *kshark_ctx(nullptr);
-	int sd, *streamIds;
+	int ret;
+	int sd;
+	int i;
 
 	if (!kshark_instance(&kshark_ctx))
 		return;
 
-	_sdHost = sdHost;
-	_vcpus = vcpus;
+	kshark_tracecmd_free_hostguest_map(_guestMap, _guestMapCount);
+	_guestMap = nullptr;
+	_guestMapCount = 0;
+	ret = kshark_tracecmd_get_hostguest_mapping(&_guestMap);
+	if (ret > 0)
+		_guestMapCount = ret;
+
 	KsUtils::setElidedText(&_hostFileLabel,
-			       kshark_ctx->stream[sdHost]->file,
+			       kshark_ctx->stream[_guestMap[0].host_id]->file,
 			       Qt::ElideLeft, LABEL_WIDTH);
 
-	streamIds = kshark_all_streams(kshark_ctx);
-	for (int i = 0; i < kshark_ctx->n_streams; ++i) {
-		sd = streamIds[i];
-		if (sd == sdHost)
+	_guestStreamComboBox.clear();
+	for (i = 0; i < _guestMapCount; i++) {
+		sd = _guestMap[i].guest_id;
+		if (sd >= kshark_ctx->n_streams)
 			continue;
 
 		_guestStreamComboBox.addItem(kshark_ctx->stream[sd]->file,
@@ -200,8 +225,8 @@ void KsComboPlotDialog::update(int sdHost, VCPUVector vcpus)
 				this,		&KsComboPlotDialog::_applyPress);
 	}
 
-	_vcpuTree.update(sdHost, vcpus);
-	free(streamIds);
+	sd = _guestStreamComboBox.currentData().toInt();
+	_vcpuTree.update(sd, _guestMap, _guestMapCount);
 }
 
 void KsComboPlotDialog::_applyPress()
@@ -210,6 +235,16 @@ void KsComboPlotDialog::_applyPress()
 	QVector<int> allCombosVec;
 	KsComboPlot combo(2);
 	int nPlots(0);
+	int GuestId;
+	int j;
+
+	GuestId = _guestStreamComboBox.currentData().toInt();
+	for (j = 0; j < _guestMapCount; j++)
+		if (_guestMap[j].guest_id == GuestId)
+			break;
+	if (j == _guestMapCount)
+		return;
+
 
 	/*
 	 * Disconnect _applyButton. This is done in order to protect
@@ -218,17 +253,20 @@ void KsComboPlotDialog::_applyPress()
 	disconnect(_applyButtonConnection);
 
 	for (auto const &i: cbVec) {
+		if (i >= _guestMap[j].vcpu_count)
+			continue;
+
 		allCombosVec.append(2);
 
-		combo[0]._streamId = _guestStreamComboBox.currentData().toInt();
-		combo[0]._id = _vcpus.at(i).second;
+		combo[0]._streamId = _guestMap[j].guest_id;
+		combo[0]._id = i;
 		combo[0]._type = KsPlot::KSHARK_CPU_DRAW |
 				 KsPlot::KSHARK_GUEST_DRAW;
 
 		combo[0] >> allCombosVec;
 
-		combo[1]._streamId = _sdHost;
-		combo[1]._id = _vcpus.at(i).first;
+		combo[1]._streamId = _guestMap[j].host_id;
+		combo[1]._id = _guestMap[j].cpu_pid[i];
 		combo[1]._type = KsPlot::KSHARK_TASK_DRAW |
 				 KsPlot::KSHARK_HOST_DRAW;
 
@@ -241,66 +279,8 @@ void KsComboPlotDialog::_applyPress()
 
 void KsComboPlotDialog::_guestStreamChanged(const QString &sdStr)
 {
-
-}
-
-static int getVCPU(plugin_kvm_context *plugin_ctx,
-		   kshark_trace_histo *histo,
-		   int sdHost, int pid)
-{
-	int values[2] = {plugin_ctx->vm_entry_id, pid};
-	const kshark_entry *entry;
-	unsigned long long vcpu;
-
-	for (int b = 0; b < histo->n_bins; ++b) {
-		entry = ksmodel_get_entry_front(histo,
-						b, false,
-						kshark_match_event_and_pid,
-						sdHost, values,
-						nullptr,
-						nullptr);
-		if (!entry)
-			continue;
-
-		if (kshark_read_event_field(entry, "vcpu_id", &vcpu) >= 0)
-			return vcpu;
-	}
-
-	return -1;
-}
-
-HostMap getVCPUPids(kshark_context *kshark_ctx, kshark_trace_histo *histo)
-{
-	int sd, n_vcpus, *streamIds, *pids;
-	plugin_kvm_context *plugin_ctx;
-	HostMap hMap;
-
-	streamIds = kshark_all_streams(kshark_ctx);
-	for (int i = 0; i < kshark_ctx->n_streams; ++i) {
-		sd = streamIds[i];
-		plugin_ctx = get_kvm_context(sd);
-		if (!plugin_ctx)
-			continue;
-
-		/* This stream contains KVM events. */
-		n_vcpus = plugin_ctx->vcpu_pids->count;
-		if (n_vcpus) {
-			VCPUVector vcpus(n_vcpus);
-			pids = kshark_hash_ids(plugin_ctx->vcpu_pids);
-			for (int j = 0; j < n_vcpus; ++j) {
-				vcpus[j].first = pids[j];
-				vcpus[j].second = getVCPU(plugin_ctx,
-							  histo,
-							  sd, pids[j]);
-			}
-
-			free(pids);
-			hMap[sd] = vcpus;
-		}
-	}
-
-	free(streamIds);
-	return hMap;
+	int GuestId = _guestStreamComboBox.currentData().toInt();
+	_vcpuTree.update(GuestId, _guestMap, _guestMapCount);
 }
 
 KsComboPlotDialog dialog;
@@ -309,18 +289,11 @@ QMetaObject::Connection dialogConnection;
 static void showDialog(KsMainWindow *ks)
 {
 	kshark_context *kshark_ctx(nullptr);
-	kshark_trace_histo *histo;
-	VCPUVector vcpus;
-	HostMap hMap;
-	int sdHost;
 
 	if (!kshark_instance(&kshark_ctx))
 		return;
 
-	histo = ks->graphPtr()->glPtr()->model()->histo();
-	hMap = getVCPUPids(kshark_ctx, histo);
-
-	if (kshark_ctx->n_streams < 2 || hMap.count() != 1) {
+	if (kshark_ctx->n_streams < 2) {
 		QString err("Data from one Host and at least one Guest is required.");
 		QMessageBox msgBox;
 		msgBox.critical(nullptr, "Error", err);
@@ -328,10 +301,7 @@ static void showDialog(KsMainWindow *ks)
 		return;
 	}
 
-	sdHost = hMap.begin().key();
-	vcpus = hMap.begin().value();
-
-	dialog.update(sdHost, vcpus);
+	dialog.update();
 
 	if (!dialogConnection) {
 		dialogConnection =
diff --git a/src/plugins/KVMCombo.hpp b/src/plugins/KVMCombo.hpp
index b47f557..ecb9aeb 100644
--- a/src/plugins/KVMCombo.hpp
+++ b/src/plugins/KVMCombo.hpp
@@ -15,10 +15,6 @@
 #include "KsMainWindow.hpp"
 #include "KsWidgetsLib.hpp"
 
-typedef QVector<QPair<int, int>> VCPUVector;
-
-typedef QMap<int, VCPUVector> HostMap;
-
 /**
  * The KsVCPUCheckBoxWidget class provides a widget for selecting CPU plots to
  * show.
@@ -27,7 +23,8 @@ struct KsVCPUCheckBoxWidget : public KsWidgetsLib::KsCheckBoxTreeWidget
 {
 	explicit KsVCPUCheckBoxWidget(QWidget *parent = nullptr);
 
-	void update(int sdHost, VCPUVector vcpus);
+	void update(int GuestId,
+		    struct kshark_host_guest_map *gMap, int gMapCount);
 };
 
 /**
@@ -39,17 +36,16 @@ class KsComboPlotDialog : public QDialog
 	Q_OBJECT
 public:
 	explicit KsComboPlotDialog(QWidget *parent = nullptr);
-
-	void update(int sdHost, VCPUVector vcpus);
+	~KsComboPlotDialog();
+	void update();
 
 signals:
 	/** Signal emitted when the "Apply" button is pressed. */
 	void apply(int sd, QVector<int>);
 
 private:
-	int				_sdHost;
-
-	VCPUVector			_vcpus;
+	int				_guestMapCount;
+	struct kshark_host_guest_map 	*_guestMap;
 
 	KsVCPUCheckBoxWidget		_vcpuTree;
 
-- 
2.25.3


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