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 16:00:13 UTC 2013
On 03/21/2013 04:31 PM, Peter Levart wrote:
> Hi Laurent, Mandy,
>
> Let me try one more time (it would be less optimal to have 2 switch
> statements instead of one). Here's the 3rd webrev:
>
> http://dl.dropbox.com/u/101777488/jdk8-tl/PlatformLogger/webrev.03/index.html
>
> The changes:
> - added the comments
> - made LevelEnum private (to not be tempted to be used from outside
> the PlatformLogger)
Hi Mandy,
JavaLogger and LoggerProxy are only used from within PlatformLogger.
Wouldn't it be better to declare them private? Their usage (one or the
other) depends on the 'loggingSupport' flag that is initialized with
PlatformLogger class. Usage of JavaLogger or LoggerProxy outside
PlatformLogger would be wrong, I think.
> - used the loggingEnabled flag as a pre-check when trying to parse the
> level objects
I think this pre-check is optimal and does not even try to load the
LoggingSupport class unless loggingEnabled is true. I tried the
following test:
public class TestLazyClassInit {
private static final boolean FALSE =
Boolean.getBoolean("non.existent.property");
static class Foo {
static {
System.out.println("Foo initialized");
}
static boolean isOk() {
return true;
}
}
public static void main(String[] args) {
if (FALSE && Foo.isOk()) {
System.out.println("FALSE is true");
} else {
System.out.println("FALSE is false");
}
}
}
... and it only prints: "FALSE is false"...
Regards, Peter
>
> What do you think?
>
> Regards, Peter
>
> On 03/21/2013 04:06 PM, Laurent Bourgès wrote:
>> Thanks Mandy for the clarifications !
>>
>> Peter, I propose to:
>> - move the LevelEnum into the JavaLogger class in order to initialize
>> it as later as possible i.e. after j.u.l calls redirectPlatformLoggers()
>> - only use it in JavaLogger class (private enum) so revert changes to
>> PlatformLogger and LoggerProxy classes
>> - add few comments in the code to explain lazy initialization (see
>> mandy's answer)
>>
>> Finally, could you keep my comment before the switch case (high
>> occurences first) ?
>> + static LevelEnum forValue(int levelValue) {
>>
>> + // higher occurences first (finest, fine, finer, info)
>> + // based on isLoggable(level) calls (03/20/2013)
>> + // in jdk project only (including generated sources)
>>
>> + switch (levelValue) {
>> + case PlatformLogger.FINEST: return FINEST; // 116 + 2257 matches in generated files
>> + case PlatformLogger.FINE: return FINE; // 270
>>
>> + case PlatformLogger.FINER: return FINER; // 157
>> + case PlatformLogger.INFO: return INFO; // 39
>> + case PlatformLogger.WARNING: return WARNING; // 12
>>
>> + case PlatformLogger.CONFIG: return CONFIG; // 6
>> + case PlatformLogger.SEVERE: return SEVERE; // 1
>> + case PlatformLogger.OFF: return OFF; // 0
>>
>> + case PlatformLogger.ALL: return ALL; // 0
>> + default: return UNKNOWN;
>> + }
>>
>> + }
>>
>> cheers,
>> Laurent
>>
>> 2013/3/21 Mandy Chung <mandy.chung at oracle.com
>> <mailto:mandy.chung at oracle.com>>
>>
>> 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[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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