8010309 : PlatformLogger: isLoggable performance / waste due to HashMap<Integer, Level> leads to Integer allocations (boxing)
Peter Levart
peter.levart at gmail.com
Thu Mar 21 15:06:20 UTC 2013
Hi Laurent,
I checked and LoggingSupport.isAvailable() can only return false in two
situations:
- no "java.util.logging.LoggingProxyImpl" class is found (but that is a
permanent condition and almost all LoggingSupport methods are
non-operational in that case)
- there is a circularity of class initialization present and a dependent
class tries to use LoggingSupport before it's static final field is set.
That is only possible if java.util.logging.LoggingProxyImpl
initialization caused that circularity. LoggingProxyImpl is only
dependent on sun.util.logging.LoggingProxy interface which has no static
initializers and LoggingProxyImpl has a simple static initializer
setting static final INSTANCE field to a singleton instance and it has
an empty private constructor. Therefore no class initialization
circularity is possible in this situation (I think).
Regards, Peter
On 03/21/2013 03:45 PM, 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[IDX_FINEST];
>> // 116 + 2257 matches in generated files
>> 524 case FINE : return
>> levelObjects[IDX_FINE]; // 270
>> 525 case FINER : return
>> levelObjects[IDX_FINER]; // 157
>> 526 case INFO : return
>> levelObjects[IDX_INFO]; // 39
>> 527 case WARNING : return
>> levelObjects[IDX_WARNING]; // 12
>> 528 case CONFIG : return
>> levelObjects[IDX_CONFIG]; // 6
>> 529 case SEVERE : return
>> levelObjects[IDX_SEVERE]; // 1
>> 530 case OFF : return
>> levelObjects[IDX_OFF]; // 0
>> 531 case ALL : return
>> levelObjects[IDX_ALL]; // 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/view_bug.do?bug_id=
>> 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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