On Fri, 18 Jun 2021 07:31:14 GMT, Сергей Цыпанов <github.com+10835776+stsypa...@openjdk.org> wrote:
> There is an optimization opportunity for the widespread use-case when a > resource is read from classpath using > `getClass().getClassLoader().getResource()` or > `getClass().getClassLoader().getResourceAsStream()`. > > Pay attention to lines starting from 261. In case I run something like > > var props = > getClass().getClassLoader().getResource("/application.properties"); > > I get into the if-else block starting from 251 and here 'separator' variable > is an empty String. In this case we can skip 'separator' from concatenation > chain and use `String.concat()` as there are only two items concatenated. > > In the opposite case `separator` variable is `"/"` and at the same time `ind` > variable is `-1`. This means that expression `path.substring(0, ind + 1)` > always returns an empty String and again can be excluded from concatenation > chain allowing usage of `String.concat()` which allows to dodge utilization > of `StringBuilder` (here `StringConcatFactory` is not available, see > https://github.com/openjdk/jdk/pull/3627) > > In the next else-block, starting from 274, again, `String.concat()` is > applicable. > > In another if-else block, starting from 277, when id is 0 again > path.substring(0, ind) returns empty String making concatenation pointless > and avoidable. > > There are also some other minor clean-ups possible regarding constant > conditions (lines 252 and 161). > > The change allows to reduce significantly resource look-up costs for a very > wide-spread case: > > @State(Scope.Benchmark) > @BenchmarkMode(Mode.AverageTime) > @OutputTimeUnit(TimeUnit.NANOSECONDS) > @Fork(jvmArgsAppend = {"-Xms2g", "-Xmx2g"}) > public class ClassGetResourceBenchmark { > private final Class<?> clazz = getClass(); > > @Benchmark > public URL getResource() { > return clazz.getResource("/application.properties"); > } > } > > The change allows to reduce memory consumption significantly: > > before > > Benchmark Mode > Cnt Score Error Units > ClassGetResourceBenchmark.getResource avgt > 100 1649,367 ± 5,904 ns/op > ClassGetResourceBenchmark.getResource:·gc.alloc.rate avgt > 100 619,204 ± 2,413 MB/sec > ClassGetResourceBenchmark.getResource:·gc.alloc.rate.norm avgt > 100 1339,232 ± 4,909 B/op > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Eden_Space avgt > 100 627,192 ± 74,972 MB/sec > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Eden_Space.norm avgt > 100 1356,681 ± 162,354 B/op > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Survivor_Space avgt > 100 0,119 ± 0,100 MB/sec > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Survivor_Space.norm avgt > 100 0,257 ± 0,217 B/op > ClassGetResourceBenchmark.getResource:·gc.count avgt > 100 128,000 counts > ClassGetResourceBenchmark.getResource:·gc.time avgt > 100 227,000 ms > > after > > Benchmark Mode > Cnt Score Error Units > ClassGetResourceBenchmark.getResource avgt > 100 1599,948 ± 4,115 ns/op > ClassGetResourceBenchmark.getResource:·gc.alloc.rate avgt > 100 358,434 ± 0,922 MB/sec > ClassGetResourceBenchmark.getResource:·gc.alloc.rate.norm avgt > 100 752,016 ± 0,004 B/op > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Eden_Space avgt > 100 342,778 ± 76,490 MB/sec > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Eden_Space.norm avgt > 100 719,264 ± 160,513 B/op > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Survivor_Space avgt > 100 0,008 ± 0,005 MB/sec > ClassGetResourceBenchmark.getResource:·gc.churn.G1_Survivor_Space.norm avgt > 100 0,017 ± 0,010 B/op > ClassGetResourceBenchmark.getResource:·gc.count avgt > 100 70,000 counts > ClassGetResourceBenchmark.getResource:·gc.time avgt > 100 151,000 ms Hi Daniel, tier1 and tier2 is ok in pipeline, but locally I'm facing Test selection 'jdk:tier1', will run: * jtreg:test/jdk:tier1 Running test 'jtreg:test/jdk:tier1' Error: Unexpected exception occurred! java.lang.IllegalArgumentException: 6+1 java.lang.IllegalArgumentException: 6+1 at com.sun.javatest.regtest.tool.Version.<init>(Version.java:80) at com.sun.javatest.regtest.config.TestProperties$Cache$Entry.initAllowSmartActionArgs(TestProperties.java:452) at com.sun.javatest.regtest.config.TestProperties$Cache$Entry.<init>(TestProperties.java:262) at com.sun.javatest.regtest.config.TestProperties$Cache.getEntryInternal(TestProperties.java:509) at com.sun.javatest.regtest.config.TestProperties$Cache.getEntry(TestProperties.java:500) at com.sun.javatest.regtest.config.TestProperties.<init>(TestProperties.java:57) at com.sun.javatest.regtest.config.RegressionTestSuite.<init>(RegressionTestSuite.java:80) at com.sun.javatest.regtest.config.RegressionTestSuite.open(RegressionTestSuite.java:65) at com.sun.javatest.regtest.config.TestManager.getTestSuites(TestManager.java:165) at com.sun.javatest.regtest.tool.Tool.run(Tool.java:1124) at com.sun.javatest.regtest.tool.Tool.run(Tool.java:1075) at com.sun.javatest.regtest.tool.Tool.main(Tool.java:147) at com.sun.javatest.regtest.Main.main(Main.java:58) Finished running test 'jtreg:test/jdk:tier1' Test report is stored in build/linux-x86_64-server-release/test-results/jtreg_test_jdk_tier1 I configure and run tests with > bash configure --with-boot-jdk=/home/s.tsypanov/jdks/jdk-16.0.1 > --with-jtreg=/home/s.tsypanov/jtreg5 > make test TEST=jdk:tier1 && make test TEST=jdk:tier2 ------------- PR: https://git.openjdk.java.net/jdk/pull/4526