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#20830 closed enhancement (fixed)

Reduce heap size of org.openstreetmap.josm.data.osm.Node by 8 bytes

Reported by: simon04 Owned by: simon04
Priority: normal Milestone: 21.05
Component: Core Version:
Keywords: heap profiling intellij yourkit Cc:

Description

We can save 8 bytes for each org.openstreetmap.josm.data.osm.Node instance by moving the mappaintCacheIdx from OsmPrimitive to AbstractPrimitive due to Java's memory layout alignment.

BEFORE org.openstreetmap.josm.data.osm.Node object internals:
 OFFSET  SIZE         TYPE DESCRIPTION                               VALUE
      0    16              (object header)                           N/A
     16     8         long AbstractPrimitive.id                      N/A
     24     4          int AbstractPrimitive.version                 N/A
     28     4          int AbstractPrimitive.changesetId             N/A
     32     4          int AbstractPrimitive.timestamp               N/A
     36     2        short AbstractPrimitive.flags                   N/A
     38     2              (alignment/padding gap)                  
     40     8         User AbstractPrimitive.user                    N/A
     48     8     String[] AbstractPrimitive.keys                    N/A
     56     2        short OsmPrimitive.mappaintCacheIdx             N/A
     58     6              (alignment/padding gap)                  
     64     8   StyleCache OsmPrimitive.mappaintStyle                N/A
     72     8      DataSet OsmPrimitive.dataSet                      N/A
     80     8       Object OsmPrimitive.referrers                    N/A
     88     8       double Node.lat                                  N/A
     96     8       double Node.lon                                  N/A
    104     8       double Node.east                                 N/A
    112     8       double Node.north                                N/A
    120     8       Object Node.eastNorthCacheKey                    N/A
Instance size: 128 bytes
Space losses: 8 bytes internal + 0 bytes external = 8 bytes total
  • src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java

    diff --git a/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java b/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java
    index 591048789..47262617a 100644
    a b public abstract class AbstractPrimitive implements IPrimitive { 
    135135     */
    136136    protected volatile short flags = FLAG_VISIBLE;   // visible per default
    137137
     138    /**
     139     * The mappaint cache index for this primitive.
     140     * This field belongs to {@code OsmPrimitive}, but due to Java's memory layout alignment
     141     */
     142    protected short mappaintCacheIdx;
     143
    138144    /*-------------------
    139145     * OTHER PROPERTIES
    140146     *-------------------*/
  • src/org/openstreetmap/josm/data/osm/OsmPrimitive.java

    diff --git a/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java b/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java
    index 764e4e1d3..496751f98 100644
    a b public abstract class OsmPrimitive extends AbstractPrimitive implements Template 
    145145     * MAPPAINT
    146146     *--------*/
    147147    private StyleCache mappaintStyle;
    148     private short mappaintCacheIdx;
    149148
    150149    @Override
    151150    public final StyleCache getCachedStyle() {
AFTER org.openstreetmap.josm.data.osm.Node object internals:
 OFFSET  SIZE         TYPE DESCRIPTION                               VALUE
      0    16              (object header)                           N/A
     16     8         long AbstractPrimitive.id                      N/A
     24     4          int AbstractPrimitive.version                 N/A
     28     4          int AbstractPrimitive.changesetId             N/A
     32     4          int AbstractPrimitive.timestamp               N/A
     36     2        short AbstractPrimitive.flags                   N/A
     38     2        short AbstractPrimitive.mappaintCacheIdx        N/A
     40     8         User AbstractPrimitive.user                    N/A
     48     8     String[] AbstractPrimitive.keys                    N/A
     56     8   StyleCache OsmPrimitive.mappaintStyle                N/A
     64     8      DataSet OsmPrimitive.dataSet                      N/A
     72     8       Object OsmPrimitive.referrers                    N/A
     80     8       double Node.lat                                  N/A
     88     8       double Node.lon                                  N/A
     96     8       double Node.east                                 N/A
    104     8       double Node.north                                N/A
    112     8       Object Node.eastNorthCacheKey                    N/A
Instance size: 120 bytes
Space losses: 0 bytes internal + 0 bytes external = 0 bytes total

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Change History (1)

comment:1 Changed 13 months ago by simon04

Resolution: fixed
Status: assignedclosed

In 17849/josm:

fix #20830 - Reduce heap size of org.openstreetmap.josm.data.osm.Node by 8 bytes

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