From kde-core-devel  Tue Sep 09 13:09:38 2003
From: Ian Reinhart Geiser <geiseri () yahoo ! com>
Date: Tue, 09 Sep 2003 13:09:38 +0000
To: kde-core-devel
Subject: KConfig sync speedup patch rev 1
X-MARC-Message: https://marc.info/?l=kde-core-devel&m=106311326417205
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Hi,
	At n7y I worked out this patch with the help of david.  It seems to speed =
up=20
some apps when i measure them with calltree.  The issue was that before thi=
s=20
patch every time you call sync the config file is reparsed.  This patch=20
causes the config file not to be reparsed unless it has changed on disk sin=
ce=20
the last write.

	In kmail with calltree without it I seem to see 10% of startup time spent =
in=20
KConfigINIBackend::sync(), where as after the patch it only spends about=20
7%....  Im still not sure if these numbers are accurate, so im hopeful othe=
rs=20
can test, modify this patch.

	The idea is that a stat and compair of QDateTime is faster than the repars=
e. =20

	Thanks
	-ian reinhart geiser
=2D --=20
=2D --:Ian Reinhart Geiser <geiseri@yahoo.com>
=2D --:Public Key: http://geiseri.myip.org/~geiseri/publickey.asc
=2D --:Public Calender: http://geiseri.myip.org/~geiseri/publicevents.ics
=2D --:Jabber: geiseri@geiseri.myip.org
=2D --:Be an optimist -- at least until they start moving animals in=20
=2D --:   pairs to Cape Canaveral. ~ Source Unknown
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Index: kconfigbackend.h
===================================================================
RCS file: /home/kde/kdelibs/kdecore/kconfigbackend.h,v
retrieving revision 1.30
diff -u -r1.30 kconfigbackend.h
--- kconfigbackend.h	30 Aug 2003 07:33:48 -0000	1.30
+++ kconfigbackend.h	9 Sep 2003 13:08:53 -0000
@@ -24,6 +24,7 @@
 
 #include "kconfigdata.h"
 #include <kconfigbase.h>
+#include <qdatetime.h>
 #include "kdemacros.h"
 
 class QFile;
@@ -280,6 +281,7 @@
   virtual void virtual_hook( int id, void* data );
 private:
   KConfigINIBackEndPrivate *d;
+  QDateTime bModTime;
 };
 
 #endif
Index: kconfigbackend.cpp
===================================================================
RCS file: /home/kde/kdelibs/kdecore/kconfigbackend.cpp,v
retrieving revision 1.82
diff -u -r1.82 kconfigbackend.cpp
--- kconfigbackend.cpp	7 Sep 2003 20:37:32 -0000	1.82
+++ kconfigbackend.cpp	9 Sep 2003 13:08:54 -0000
@@ -198,6 +198,7 @@
 
 bool KConfigINIBackEnd::parseConfigFiles()
 {
+  //qDebug("Trying to parse %s\n", mLocalFileName.latin1());
   // Check if we can write to the local file.
   mConfigState = KConfigBase::ReadOnly;
   if (!mLocalFileName.isEmpty() && !pConfig->isReadOnly())
@@ -295,6 +296,9 @@
   if (bFileImmutable)
      mConfigState = KConfigBase::ReadOnly;
 
+  QFileInfo info(mLocalFileName);
+  bModTime = info.lastModified();
+
   return true;
 }
 
@@ -311,6 +315,29 @@
 #endif
 #endif
 
+#include <execinfo.h>
+#include <stdlib.h>
+
+static QString qBacktrace( int levels = -1 )
+{
+    QString s;
+    void* trace[256];
+    int n = backtrace(trace, 256);
+    char** strings = backtrace_symbols (trace, n);
+
+    if ( levels != -1 )
+        n = QMIN( n, levels );
+    s = "[\n";
+
+    for (int i = 0; i < n; ++i)
+        s += QString::number(i) +
+             QString::fromLatin1(": ") +
+             QString::fromLatin1(strings[i]) + QString::fromLatin1("\n");
+    s += "]\n";
+    free (strings);
+    return s;
+}
+
 void KConfigINIBackEnd::parseSingleConfigFile(QFile &rFile,
 					      KEntryMap *pWriteBackMap,
 					      bool bGlobal, bool bDefault)
@@ -322,9 +349,9 @@
 
    //using kdDebug() here leads to an infinite loop
    //remove this for the release, aleXXX
-   //qWarning("Parsing %s, global = %s default = %s",
-   //           rFile.name().latin1(), bGlobal ? "true" : "false", bDefault ? "true" : "false");
-
+   //qDebug("Parsing %s, global = %s default = %s\n",
+    //          rFile.name().latin1(), bGlobal ? "true" : "false", bDefault ? "true" : "false");
+   //qDebug("%s",qBacktrace().latin1());
    QCString aCurrentGroup("<default>");
 
    const char *s, *eof;
@@ -712,8 +739,20 @@
 {
   bool bEntriesLeft = false;
   bFileImmutable = false;
+  // Check if the file has been updated.
+  bool isMod = false;
   if (mergeFile)
   {
+	QFileInfo info(*mergeFile);
+	if (info.lastModified() > bModTime)
+	{
+		isMod = true;
+	}
+  }
+
+  if (mergeFile && isMod)
+  {
+
     // Read entries from disk
     if (mergeFile->open(IO_ReadOnly))
     {
@@ -825,6 +864,7 @@
      if (pConfigFile->status() != 0)
      {
         delete pConfigFile;
+        pConfigFile = 0L;
         return bEntriesLeft;
      }
 
@@ -870,11 +910,16 @@
         pConfigFile->close();
      }
      delete pConfigFile;
+     pConfigFile = 0L;
   }
   else
   {
      fclose(pStream);
   }
+
+  // Update time stamp
+  QFileInfo info(filename);
+  bModTime = info.lastModified();
 
   return bEntriesLeft;
 }

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