andi/perfdb
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reduce memory allocations by 25% with a cache of formatted longs

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This commit is contained in:
Andreas Huber
2017-09-24 09:53:25 +02:00
parent 37eb05aebf
commit 8b74992e66
1 changed files with 21 additions and 1 deletions
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22
pdb-plotting/src/main/java/org/lucares/recommind/logs/Plotter.java
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@@ -39,6 +39,17 @@ public class Plotter {
private static final String DEFAULT_GROUP = "<none>";
private static final int INT_TO_STRING_CACHE_SIZE= 1000;
private static final String[] INT_TO_STRING;
static {
INT_TO_STRING = new String[INT_TO_STRING_CACHE_SIZE];
for (int i = 0; i < INT_TO_STRING_CACHE_SIZE; i++){
INT_TO_STRING[i] = String.valueOf(i);
}
}
private final PerformanceDb db;
private final Path tmpBaseDir;
private final Path outputDir;
@@ -234,7 +245,7 @@ public class Plotter {
if (fromEpochMilli <= entry.getEpochMilli() && entry.getEpochMilli() <= toEpochMilli) {
final String value = String.valueOf(entry.getValue());
final String value = longToString(entry.getValue());
final String formattedDate;
if (useMillis){
@@ -261,4 +272,13 @@ public class Plotter {
METRICS_LOGGER.debug("wrote {} values to csv in: {}ms (ignored {} values) use millis: {}", count, (System.nanoTime() - start) / 1_000_000.0, ignoredValues, Boolean.toString(useMillis));
return new CsvSummary(count, maxValue);
}
private static String longToString(final long value){
// using pre-generated strings reduces memory allocation by up to 25%
if (value < INT_TO_STRING_CACHE_SIZE){
return INT_TO_STRING[(int) value];
}
return String.valueOf(value);
}
}