Differential D23105 Diff 64185 helpers/perf/ftrace_marker.cpp

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helpers/perf/ftrace_marker.cpp

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		1		/********************************************************************
		2		KWin - the KDE window manager
		3		This file is part of the KDE project.
		4
		5		Copyright 2019 Roman Gilg <subdiff@gmail.com>
		6
		7		This program is free software; you can redistribute it and/or modify
		8		it under the terms of the GNU General Public License as published by
		9		the Free Software Foundation; either version 2 of the License, or
		10		(at your option) any later version.
		11
		12		This program is distributed in the hope that it will be useful,
		13		but WITHOUT ANY WARRANTY; without even the implied warranty of
		14		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		15		GNU General Public License for more details.
		16
		17		You should have received a copy of the GNU General Public License
		18		along with this program. If not, see <http://www.gnu.org/licenses/>.
		19		*********************************************************************/
		20		#include "ftrace_marker.h"
		21
		22		#include "utils.h"
		23
		24		#include <QDir>
		25		#include <QFileInfo>
		26
		27		namespace KWin
		28		{
		29		namespace Perf
		30		{
		31
		32		void writeFunctionEnabled(QFile *file, const QString &message)
		33		{
		34		file->write(message.toLatin1());
		35		file->flush();
		36		}
		37
		38		void writeFunctionDisabled(QFile *file, const QString &message)
		39		{
		40		Q_UNUSED(file)
		41		Q_UNUSED(message)
		42		}
		43
		44		void (s_writeFunction)(QFile file, const QString &message) = writeFunctionDisabled;
		45
		46
		47		KWIN_SINGLETON_FACTORY(FtraceMarker)
		48
		49		FtraceMarker::FtraceMarker(QObject *parent)
		50		: QObject(parent)
		51		{
		52		if (qEnvironmentVariableIsSet("KWIN_PERF_FTRACE")) {
		53		qCDebug(KWIN_PERF) << "Ftrace marking initially enabled via environment variable";
		54		setEnabled(true);
		55		}
		56		}
		57
		58		bool FtraceMarker::setEnabled(bool enable)
		59		{
		60		if ((bool)m_file == enable) {
		61		// no change
		62		return true;
		63		}
		64		if (enable) {
		65		if (!findFile()) {
		66		qCWarning(KWIN_PERF) << "Ftrace marking not available. Try reenabling after issue is solved.";
		67		return false;
		68		}
		69		s_writeFunction = writeFunctionEnabled;
		70		} else {
		71		s_writeFunction = writeFunctionDisabled;
		72		delete m_file;
		73		m_file = nullptr;
		74		}
		75		return true;
		76		}
		77
		78		void FtraceMarker::print(const QString &message)
		79		{
		80		(*s_writeFunction)(m_file, message);
		81		}
		82
		83		void FtraceMarker::print(ulong ctx, const QString &message)
		84		{
		85		(*s_writeFunction)(m_file, message + QStringLiteral(" (begin_ctx=%1)").arg(ctx));
		86		}
		87
		88		void FtraceMarker::print(const QString &message, ulong ctx)
		89		{
		90		(*s_writeFunction)(m_file, message + QStringLiteral(" (end_ctx=%1)").arg(ctx));
		91		}
		92
		93		bool FtraceMarker::findFile()
		94		{
		95		QFile mountsFile("/proc/mounts");
		96		if (!mountsFile.open(QIODevice::ReadOnly \| QIODevice::Text)) {
		97		qCWarning(KWIN_PERF) << "No acces to mounts file. Can not determine trace marker file location.";
		98		return false;
		99		}
		100
		101		auto setInfo = [](const QString &line) {
		102		const int start = line.indexOf(' ') + 1;
		103		const int end = line.indexOf(' ', start);
		104		return QFileInfo(QDir(line.mid(start, end - start)),
		105		QString::fromLatin1("trace_marker"));
		106		};
		107		QFileInfo markerFileInfo;
		108		QTextStream mountsIn(&mountsFile);
		109		QString mountsLine = mountsIn.readLine();
		110
		111		while (!mountsLine.isNull()) {
		112		if (mountsLine.startsWith("tracefs")) {
		113		markerFileInfo = setInfo(mountsLine);
		114		break;
		115		}
		116		if (mountsLine.startsWith("debugfs")) {
		117		markerFileInfo = setInfo(mountsLine);
		118		}
		119		mountsLine = mountsIn.readLine();
		120		}
		121		mountsFile.close();
		122
		123		const QString path = markerFileInfo.absoluteFilePath();
		124		m_file = new QFile(path, this);
		125		if (!m_file->open(QIODevice::WriteOnly)) {
		126		qCWarning(KWIN_PERF) << "No access to trace marker file at:" << path;
		127		delete m_file;
		128		m_file = nullptr;
		129		return false;
		130		}
		131		return true;
		132		}
		133
		134		}
		135		}