add perf query interface and untangle it from recordpage

moving the query part of the recordpage into its own class will make
implementing remote recording much easier

Author: lievenhey

src/CMakeLists.txt

@@ -53,6 +53,7 @@ set(HOTSPOT_SRCS
     initiallystoppedprocess.cpp
     perfcontrolfifowrapper.cpp
     errnoutil.cpp
+    recordhost.cpp
     # ui files:
     mainwindow.ui
     aboutdialog.ui
@@ -73,6 +74,7 @@ set(HOTSPOT_SRCS
     callgraphsettingspage.ui
     frequencypage.ui
     sourcepathsettings.ui
+    perfsettingspage.ui
     # resources:
     resources.qrc
 )

src/jobtracker.h

@@ -0,0 +1,63 @@
+/*
+    SPDX-FileCopyrightText: Lieven Hey <[email protected]>
+    SPDX-FileCopyrightText: 2022 Klarälvdalens Datakonsult AB, a KDAB Group company, [email protected]
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include <ThreadWeaver/ThreadWeaver>
+#include <QObject>
+#include <QPointer>
+
+class JobTracker
+{
+public:
+    explicit JobTracker(QObject* context)
+        : m_context(context)
+    {
+    }
+
+    bool isJobRunning() const
+    {
+        return m_context && m_isRunning;
+    }
+
+    template<typename Job, typename SetData>
+    void startJob(Job&& job, SetData&& setData)
+    {
+        using namespace ThreadWeaver;
+        const auto jobId = ++m_currentJobId;
+        auto jobCancelled = [context = m_context, jobId, currentJobId = &m_currentJobId]() {
+            return !context || jobId != (*currentJobId);
+        };
+        auto maybeSetData = [jobCancelled, setData = std::forward<SetData>(setData),
+                             isRunning = &m_isRunning](auto&& results) {
+            if (!jobCancelled()) {
+                setData(std::forward<decltype(results)>(results));
+                *isRunning = false;
+            }
+        };
+
+        m_isRunning = true;
+        stream() << make_job([context = m_context, job = std::forward<Job>(job), maybeSetData = std::move(maybeSetData),
+                              jobCancelled = std::move(jobCancelled)]() mutable {
+            auto results = job(jobCancelled);
+            if (jobCancelled())
+                return;
+
+            QMetaObject::invokeMethod(
+                context.data(),
+                [results = std::move(results), maybeSetData = std::move(maybeSetData)]() mutable {
+                    maybeSetData(std::move(results));
+                },
+                Qt::QueuedConnection);
+        });
+    }
+
+private:
+    QPointer<QObject> m_context;
+    std::atomic<uint> m_currentJobId;
+    bool m_isRunning = false;
+};

src/perfrecord.cpp

@@ -295,90 +295,11 @@ void PerfRecord::sendInput(const QByteArray& input)
     m_perfRecordProcess->write(input);
 }
 
-QString PerfRecord::currentUsername()
-{
-    return KUser().loginName();
-}
-
-bool PerfRecord::canTrace(const QString& path)
-{
-    const auto info = QFileInfo(QLatin1String("/sys/kernel/debug/tracing/") + path);
-    if (!info.isDir() || !info.isReadable()) {
-        return false;
-    }
-    QFile paranoid(QStringLiteral("/proc/sys/kernel/perf_event_paranoid"));
-    return paranoid.open(QIODevice::ReadOnly) && paranoid.readAll().trimmed() == "-1";
-}
-
-static QByteArray perfOutput(const QStringList& arguments)
-{
-    QProcess process;
-
-    auto reportError = [&]() {
-        qWarning() << "Failed to run perf" << process.arguments() << process.error() << process.errorString()
-                   << process.readAllStandardError();
-    };
-
-    QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
-    env.insert(QStringLiteral("LANG"), QStringLiteral("C"));
-    process.setProcessEnvironment(env);
-
-    QObject::connect(&process, &QProcess::errorOccurred, &process, reportError);
-    process.start(PerfRecord::perfBinaryPath(), arguments);
-    if (!process.waitForFinished(1000) || process.exitCode() != 0)
-        reportError();
-    return process.readAllStandardOutput();
-}
-
-static QByteArray perfRecordHelp()
-{
-    static const QByteArray recordHelp = []() {
-        static QByteArray help = perfOutput({QStringLiteral("record"), QStringLiteral("--help")});
-        if (help.isEmpty()) {
-            // no man page installed, assume the best
-            help = "--sample-cpu --switch-events";
-        }
-        return help;
-    }();
-    return recordHelp;
-}
-
-static QByteArray perfBuildOptions()
-{
-    static const QByteArray buildOptions = perfOutput({QStringLiteral("version"), QStringLiteral("--build-options")});
-    return buildOptions;
-}
-
-bool PerfRecord::canProfileOffCpu()
-{
-    return canTrace(QStringLiteral("events/sched/sched_switch"));
-}
-
 QStringList PerfRecord::offCpuProfilingOptions()
 {
     return {QStringLiteral("--switch-events"), QStringLiteral("--event"), QStringLiteral("sched:sched_switch")};
 }
 
-bool PerfRecord::canSampleCpu()
-{
-    return perfRecordHelp().contains("--sample-cpu");
-}
-
-bool PerfRecord::canSwitchEvents()
-{
-    return perfRecordHelp().contains("--switch-events");
-}
-
-bool PerfRecord::canUseAio()
-{
-    return perfBuildOptions().contains("aio: [ on  ]");
-}
-
-bool PerfRecord::canCompress()
-{
-    return Zstd_FOUND && perfBuildOptions().contains("zstd: [ on  ]");
-}
-
 bool PerfRecord::canElevatePrivileges()
 {
     return !findPkexec().isEmpty();

src/perfrecord.h

@@ -33,21 +33,8 @@ class PerfRecord : public QObject
     void stopRecording();
     void sendInput(const QByteArray& input);
 
-    static QString currentUsername();
-
-    static bool canTrace(const QString& path);
-    static bool canProfileOffCpu();
-    static bool canSampleCpu();
-    static bool canSwitchEvents();
-    static bool canUseAio();
-    static bool canCompress();
-    static bool canElevatePrivileges();
-
     static QStringList offCpuProfilingOptions();
 
-    static QString perfBinaryPath();
-    static bool isPerfInstalled();
-
 signals:
     void recordingStarted(const QString& perfBinary, const QStringList& arguments);
     void recordingFinished(const QString& fileLocation);
@@ -63,6 +50,9 @@ class PerfRecord : public QObject
     bool m_userTerminated;
 
     static bool actuallyElevatePrivileges(bool elevatePrivileges);
+    static QString perfBinaryPath();
+    static bool canElevatePrivileges();
+    static bool isPerfInstalled();
 
     bool runPerf(bool elevatePrivileges, const QStringList& perfOptions, const QString& outputPath,
                  const QString& workingDirectory = QString());

src/perfsettingspage.ui

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>PerfSettingsPage</class>
+ <widget class="QWidget" name="PerfSettingsPage">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QFormLayout" name="formLayout">
+   <item row="1" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Perf Binary:</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="1">
+    <widget class="KUrlRequester" name="perfPathEdit"/>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>KUrlRequester</class>
+   <extends>QWidget</extends>
+   <header>kurlrequester.h</header>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>