8010309 : PlatformLogger: isLoggable performance / waste due to HashMap<Integer, Level (original) (raw)

Mandy Chung mandy.chung at oracle.com
Thu Mar 21 14:54:48 UTC 2013

Laurent, Peter,

I haven't looked at the patch yet. One thing worths mentioning is that PlatformLogger was added for the platform code to use so as to avoid the initialization of java.util.logging since logging is not turned on by default and that to reduce the startup overhead. In addition, it also enables the elimination of the core classes dependency from java.util.logging for modularization effort. Therefore the PlatformLogger only lazily looks up the Level object when java.util.logging is present and also has been initialized by application code.

Mandy

On 3/21/2013 7:45 AM, Peter Levart wrote:

On 03/21/2013 03:30 PM, Laurent Bourgès wrote:

Peter,

your solution looks better; I wanted my patch to be simple, efficient and only modify the JavaLogger class (localized changes). In your patch, I have doubts related to lazy and conditional initialization in JavaLogger (static initialization): if (LoggingSupport.isAvailable()) { // initialize ... } In original code, if LoggingSupport.isAvailable() returned false, levelObjects map remained empty and consequently null was used as the level object passed to LoggingSupport methods. In LevelEnum I try to keep this logic. When LevelEnum is first used, it's constants are initialized and level objects with them. If LoggingSupport.isAvailable() returns false, level objects are initialized to null. I just noticed there's a bug in initialization of the LevelEnum.UNKNOWN member constant. It should not try to parse level object. Here's an update: http://dl.dropbox.com/u/101777488/jdk8-tl/PlatformLogger/webrev.02/index.html But your concern might be correct. In my code LevelEnum is also used from the LoggerProxy.format() method (in addition to all the places in JavaLogger) to obtain the level name for formatting. If this method is called the first time while LoggingSupport.isAvailable() returns false and that happens before JavaLogger uses LevelEnum for the first time (and at that time LoggingSupport.isAvailable() would return true), then level objects will not be initialized correctly. Lazy initialization of level objects might help (for the price of added complexity)... Regards, Peter Does somebody have the knowledge about LoggingSupport.isAvailable() and the lazy PlatformLogger initialization (JavaLogger are only used when j.u.l is initialized) ?

What's happening if LoggingSupport.isAvailable() returns false in your patch ? - LevelEnum instances are incorrectly initialized:object field is null ! - PlatformLogger is then broken ... as Level object are required by j.u.l calls To fix both problems, moving theLevelEnum into JavaLogger should help and check nulls onLevelEnum.object field. Thanks for your feedback, Laurent 2013/3/21 Peter Levart <peter.levart at gmail.com_ _<mailto:peter.levart at gmail.com>> On 03/21/2013 12:12 PM, Laurent Bourgès wrote: Here is an improved patch tested on JDK7u13 and JDK8 internal build on my machine linux x64: http://jmmc.fr/~bourgesl/share/webrev-8010309/ <http://jmmc.fr/%7Ebourgesl/share/webrev-8010309/> FYI, I removed completely the Map<Integer, Object> levelObjects and used two arrays to perform the PlatformLogger's level (int) to j.u.l.Level mapping: I decided to keep it simple as possible (no enum ...) and used a switch case based on current level occurences: Hi Laurent, In my experience enums are just the right and most compact tool for coding such constant associations. Here's a quick try (ripping off your optimized switch ;-): http://dl.dropbox.com/u/101777488/jdk8-tl/PlatformLogger/webrev.01/index.html ...it adds 12 LOC to the original PlatformLogger and is 43 LOC less tha your patch. In addition: - only one switch instead of two (to maintain) - no parallel IDX constants What do you think? Regards, Peter

510 /** 511 * Return the corresponding j.u.l.Level instance 512 * @param level PlatformLogger level as integer 513 * @return Object (j.u.l.Level instance) or null if no matching level 514 */ 515 private static Object getLevel(final int level) { 516 if (levelObjects == null) { 517 return null; 518 } 519 // higher occurences first (finest, fine, finer, info) 520 // based on isLoggable(level) calls (03/20/2013) 521 // in jdk project only (including generated sources) 522 switch (level) { 523 case FINEST : return levelObjects[IDXFINEST]; // 116 + 2257 matches in generated files 524 case FINE : return levelObjects[IDXFINE]; // 270 525 case FINER : return levelObjects[IDXFINER]; // 157 526 case INFO : return levelObjects[IDXINFO]; // 39 527 case WARNING : return levelObjects[IDXWARNING]; // 12 528 case CONFIG : return levelObjects[IDXCONFIG]; // 6 529 case SEVERE : return levelObjects[IDXSEVERE]; // 1 530 case OFF : return levelObjects[IDXOFF]; // 0 531 case ALL : return levelObjects[IDXALL]; // 0 532 default : return null; 533 } 534 } I enhanced the PlatformLoggerTest class also and figured out that TLAB optimized Integer allocations but I think the patch is still useful. Can you have a look to the patch ? Should I write a jtreg test (performance / GC issue) ? Cheers, Laurent 2013/3/20 Mandy Chung <mandy.chung at oracle.com_ _<mailto:mandy.chung at oracle.com>> Hi Laurent, Thank you for signing the OCA. Your contribution is very welcome. You can submit a patch for this bug (see [1]) to Core libraries group which owns logging. Jim Gish and I will sponsor it. Thanks Mandy [1] http://openjdk.java.net/contribute/ On 3/20/2013 5:45 AM, Laurent Bourgès wrote: Hi mandy, Do you want me to propose an improved patch to remove the former Map and fix the getLevel() method ? or you prefer fix on your own ? Is it better to discuss the fix on the bug database (still not visible) ? Laurent 2013/3/19 Mandy Chung <mandy.chung at oracle.com_ _<mailto:mandy.chung at oracle.com>> Hi Laurent, Thanks for the contribution. I agree that the map can be replaced with a direct mapping from a int value to Level object and avoid the autoboxing conversion. I have filed a bug to track this and target this for JDK8: http://bugs.sun.com/bugdatabase/viewbug.do?bugid= 8010309 Thanks Mandy On 3/19/13 5:19 AM, Laurent Bourgès wrote: Dear all, I run recently netbeans profiler on my swing application (Aspro2:http://www.jmmc.fr/aspro ) under linux x64 platform and figured out a performance and waste issue related to PlatformLogger. Actually, the JavaLogger implementation uses a Map<Integer, Object> levelObjects to store mapping between PlatformLogger's levels (int) and JUL Level instances. However, the isLoggable(int level) method is highly used by awt project and other JDK projects and it leads to many Integer allocations as autoboxing converts the level as int to an Integer instance used by the Map.get() call. /** * JavaLogger forwards all the calls to its corresponding * java.util.logging.Logger object. */ static class JavaLogger extends LoggerProxy { private static final* Map<Integer, Object>* levelObjects = new HashMap<>(); ... public boolean isLoggable(int level) { return LoggingSupport.isLoggable(javaLogger, * levelObjects.get(level)*); } } I wrote a simple test to illustrate that performance / waste problem: PlatformLoggerTest that simply performs 1 million DISABLED log statements: if (log.isLoggable(PlatformLogger.FINEST)) { log.finest("test PlatformLogger.FINEST"); } As you can see in screenshots: - 5 million Integer instances are allocated - Integer.valueOf(int) is called 5 million times (autoboxing) - HashMap.get() represents 30% of the test time - patched PlatformLogger is 3x times faster [jvm options: -Xms8m -Xmx8m -verbose:gc] I suggest you to use an alternative way to map PlatformLogger's levels (int) and JUL Level instances to fix that performance / memory issue: I added the getLevel(int level) method that performs a switch case to return the corresponding Level object (quick and dirty solution). I advocate this is not a very clean solution but I prefer efficiency here: any better solution may be appropriate to avoid at least Integer allocation and maybe enhance performance. Best regards, Laurent Bourgès PS: here is the patch as text: # This patch file was generated by NetBeans IDE # It uses platform neutral UTF-8 encoding and \n newlines. --- PlatformLogger.java (6767) +++ PlatformLogger.java (6768) @@ -468,31 +468,13 @@ * java.util.logging.Logger object. */ static class JavaLogger extends LoggerProxy { - /** Note: using Integer keys leads to a lot of new Integer instances !! */ - private static final Map<Integer, Object> levelObjects = new HashMap<>(); - /** fastest mapping to Level instances from PlatformLogger level as integer */ - private static final Object[] fastLevelObjects; - - + private static final Map<Integer, Object> levelObjects = + new HashMap<>(); + static { if (LoggingSupport.isAvailable()) { // initialize the map to Level objects getLevelObjects(); - - // initialize the fastLevelObjects: - fastLevelObjects = new Object[] { - LoggingSupport.parseLevel(getLevelName(OFF)), // 0 - LoggingSupport.parseLevel(getLevelName(SEVERE)), // 1 - LoggingSupport.parseLevel(getLevelName(WARNING)), // 2 - LoggingSupport.parseLevel(getLevelName(INFO)), // 3 - LoggingSupport.parseLevel(getLevelName(CONFIG)), // 4 - LoggingSupport.parseLevel(getLevelName(FINE)), // 5 - LoggingSupport.parseLevel(getLevelName(FINER)), // 6 - LoggingSupport.parseLevel(getLevelName(FINEST)), // 7 - LoggingSupport.parseLevel(getLevelName(ALL)) // 8 - }; - } else { - fastLevelObjects = null; // check null } } @@ -515,7 +497,7 @@ this.javaLogger = LoggingSupport.getLogger(name); if (level != 0) { // level has been updated and so set the Logger's level - LoggingSupport.setLevel(javaLogger, getLevel(level)); + LoggingSupport.setLevel(javaLogger, levelObjects.get(level)); } } @@ -526,11 +508,11 @@ * not be updated. */ void doLog(int level, String msg) { - LoggingSupport.log(javaLogger, getLevel(level), msg); + LoggingSupport.log(javaLogger, levelObjects.get(level), msg); } void doLog(int level, String msg, Throwable t) { - LoggingSupport.log(javaLogger, getLevel(level), msg, t); + LoggingSupport.log(javaLogger, levelObjects.get(level), msg, t); } void doLog(int level, String msg, Object... params) { @@ -544,12 +526,12 @@ for (int i = 0; i < len; i++) { sparams [i] = String.valueOf(params[i]); } - LoggingSupport.log(javaLogger, getLevel(level), msg, sparams); + LoggingSupport.log(javaLogger, levelObjects.get(level), msg, sparams); } boolean isEnabled() { Object level = LoggingSupport.getLevel(javaLogger); - return level == null || level.equals(getLevel(OFF)) == false; + return level == null || level.equals(levelObjects.get(OFF)) == false; } int getLevel() { @@ -566,34 +548,12 @@ void setLevel(int newLevel) { levelValue = newLevel; - LoggingSupport.setLevel(javaLogger, getLevel(newLevel)); + LoggingSupport.setLevel(javaLogger, levelObjects.get(newLevel)); } public boolean isLoggable(int level) { - return LoggingSupport.isLoggable(javaLogger, getLevel(level)); + return LoggingSupport.isLoggable(javaLogger, levelObjects.get(level)); } - - /** - * Return the corresponding level object (fastest implementation) - * @param level PlatformLogger level as primitive integer - * @return Object (JUL Level instance) - */ - private static Object getLevel(final int level) { - // higher occurences first (finest, fine, finer, info): - switch (level) { - case FINEST : return fastLevelObjects[7]; - case FINE : return fastLevelObjects[5]; - case FINER : return fastLevelObjects[6]; - case INFO : return fastLevelObjects[3]; - case CONFIG : return fastLevelObjects[4]; - case WARNING : return fastLevelObjects[2]; - case SEVERE : return fastLevelObjects[1]; - case ALL : return fastLevelObjects[8]; - case OFF : return fastLevelObjects[0]; - default : return null; - } - } - } private static String getLevelName(int level) {

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