Remko Popma created LOG4J2-935:
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Summary: Performance: which String.getBytes method to use
Key: LOG4J2-935
URL: https://issues.apache.org/jira/browse/LOG4J2-935
Project: Log4j 2
Issue Type: Improvement
Components: Appenders, Core
Affects Versions: 2.1
Reporter: Remko Popma
I did some investigation to compare the performance of
{{String.getBytes(String)}} to {{String.getBytes(Charset)}} and it turns out
that the String variant is significantly faster (at least on Windows 7 and
Solaris 10).
I am not sure what causes this but the code path for
{{String.getBytes(Charset)}} leads to {{java.lang.StringCoding.encode(Charset,
char[], int, int)}} which creates a new {{StringEncoder}} for each invocation.
By contrast, {{String.getBytes(String)}} leads to
{{java.lang.StringCoding.encode(String, char[], int, int)}} which uses a cached
{{StringEncoder}} (at least in Java 6 and 7). This may be one reason.
I also compared Java 6, 7 and 8. Note that with each upgrade performance is
getting better, with a huge jump in Java 8 for ISO-8859-1 (I suspect this is
done by simply casting each char to a byte, dropping the 8 most significant
bits of each 16-bit char).
Benchmark results follow below, sorted by throughput (best first).
{{java -jar benchmarks.jar ".*StringEncodingBenchmark.*" -f 1 -t 1 -wi 5 -i 5}}
*Windows 7 (64bit) 2-core Intel i5-2500 CPU @3.30Ghz*
{noformat}
jdk1.6.0_45
Benchmark Mode Samples
Score Error Units
o.a.l.l.p.j.StringEncBenchmark.GetBytesString88591 thrpt 5
12967053.847 ± 80324.398 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSet88591 thrpt 5
6816575.144 ± 50311.921 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytes thrpt 5
3431255.953 ± 51075.510 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringDefault thrpt 5
3356148.444 ± 29690.404 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringShiftJIS thrpt 5
3339120.398 ± 13213.076 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetDefault thrpt 5
1637800.057 ± 12736.976 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetShiftJIS thrpt 5
1516240.836 ± 12076.700 ops/s
jdk1.7.0_55
Benchmark Mode Samples
Score Error Units
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSet88591 thrpt 5
13515690.815 ± 579537.298 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesString88591 thrpt 5
10818301.339 ± 60140.387 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringDefault thrpt 5
4713065.699 ± 73247.202 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytes thrpt 5
4587139.396 ± 109611.806 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetDefault thrpt 5
3629802.089 ± 38100.113 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringShiftJIS thrpt 5
3388620.097 ± 37114.869 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetShiftJIS thrpt 5
2024599.702 ± 46543.717 ops/s
jdk1.8.0_25
Benchmark Mode Samples
Score Error Units
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSet88591 thrpt 5
52009871.813 ± 502287.883 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesString88591 thrpt 5
26618044.840 ± 236755.306 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytes thrpt 5
5342101.771 ± 39781.910 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringDefault thrpt 5
5281169.402 ± 55524.193 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringShiftJIS thrpt 5
5276164.715 ± 100823.625 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetShiftJIS thrpt 5
4279903.988 ± 49535.013 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetDefault thrpt 5
3858350.559 ± 70966.741 ops/s
{noformat}
*Solaris 10 (64bit) 4-core Xeon X5570 dual CPU @2.93Ghz*
{noformat}
jdk1.6.0_20
Benchmark Mode Samples
Score Error Units
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringDefault thrpt 5
7736847.092 ± 51274.226 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytes thrpt 5
7421582.562 ± 76260.755 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesString88591 thrpt 5
6829890.456 ± 189812.619 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetDefault thrpt 5
6811579.239 ± 148393.528 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSet88591 thrpt 5
3921075.542 ± 38000.495 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringShiftJIS thrpt 5
2309217.326 ± 20982.591 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetShiftJIS thrpt 5
1029117.710 ± 14768.961 ops/s
jdk1.7.0_06
Benchmark Mode Samples
Score Error Units
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetDefault thrpt 5
12028518.507 ± 93571.792 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytes thrpt 5
11548051.157 ± 45019.349 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringDefault thrpt 5
11033635.427 ± 103410.346 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSet88591 thrpt 5
4950536.544 ± 44039.456 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesString88591 thrpt 5
4161493.706 ± 31591.263 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringShiftJIS thrpt 5
2312330.720 ± 9396.859 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetShiftJIS thrpt 5
1312534.481 ± 26186.142 ops/s
jdk1.8.0_11
Benchmark Mode Samples
Score Error Units
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSet88591 thrpt 5
33946446.764 ± 933451.351 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesString88591 thrpt 5
20917837.751 ± 257779.242 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringDefault thrpt 5
13328817.946 ± 151911.634 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytes thrpt 5
13096046.662 ± 77208.908 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetDefault thrpt 5
12356403.648 ± 170268.254 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesStringShiftJIS thrpt 5
4261255.777 ± 33116.543 ops/s
o.a.l.l.p.j.StringEncBenchmark.GetBytesCharSetShiftJIS thrpt 5
3478309.565 ± 78097.111 ops/s
{noformat}
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