8282047: Enhance StringDecode/Encode microbenchmarks by cl4es · Pull Request #7516 · openjdk/jdk

cl4es · 2022-02-17T15:11:11Z

Splitting out these micro changes from #7231

Clean up and simplify setup and code
Add variants with different inputs with varying lengths and encoding weights, but also relevant mixes of each so that we both cover interesting corner cases but also verify that performance behave when there's a multitude of input shapes. Both simple and mixed variants are interesting diagnostic tools.
Drop all charsets from the default run configuration except UTF-8. Motivation: Defaults should give good coverage but try to keep runtimes at bay. Additionally if the charset tested can't encode the higher codepoints used in these micros the results might be misleading. If you for example test using ISO-8859-1 the UTF-16 bytes in StringDecode.decodeUTF16 will have all been replaced by ?, so the test is effectively the same as testing ASCII-only.

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JDK-8282047: Enhance StringDecode/Encode microbenchmarks

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Brent Christian (@bchristi-git - Reviewer)

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bridgekeeper · 2022-02-17T15:12:21Z

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openjdk · 2022-02-17T15:14:49Z

@cl4es The following label will be automatically applied to this pull request:

core-libs

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mlbridge · 2022-02-17T15:18:27Z

Webrevs

cl4es · 2022-02-24T13:09:01Z

Ping?

bchristi-git · 2022-02-24T19:00:49Z

test/micro/org/openjdk/bench/java/lang/StringDecode.java

 @State(Scope.Thread)
 public class StringDecode {

-    @Param({"US-ASCII", "ISO-8859-1", "UTF-8", "MS932", "ISO-8859-6", "ISO-2022-KR"})


What would you think of retaining the previous set of charset names as a comment -- as a suggestion for someone who wants additional coverage?

bchristi-git · 2022-02-24T19:01:32Z

test/micro/org/openjdk/bench/java/lang/StringDecode.java

+    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+    public void decodeAsciiLong(Blackhole bh) throws Exception {
+        bh.consume(new String(longAsciiString, charset));
+        bh.consume(new String(longAsciiString, 0, 1024 + 31, charset));


I imagine the 1024+31 addition gets compiled down, and is not executed during the test, right?

Yes, adding two integer literals will be constant folded already by javac:

public static void main(String...args) { int foo = 1024 + 31; }

javap -v output:

0: sipush 1055 3: istore_1 4: return

bchristi-git · 2022-02-24T19:09:28Z

test/micro/org/openjdk/bench/java/lang/StringEncode.java

 @State(Scope.Thread)
 public class StringEncode {

-    @Param({"US-ASCII", "ISO-8859-1", "UTF-8", "MS932", "ISO-8859-6"})


Same, re: keeping list as a comment.

bchristi-git · 2022-02-24T19:16:42Z

test/micro/org/openjdk/bench/java/lang/StringDecode.java

@@ -46,22 +36,22 @@
 @State(Scope.Thread)


No change to @fork and @WarmUp (as in the Encode test)?

theRealAph · 2022-02-25T09:41:09Z

test/micro/org/openjdk/bench/java/lang/StringDecode.java

+    @Setup
+    public void setup() {
+        charset = Charset.forName(charsetName);
+        asciiString = LOREM.substring(0, 32).getBytes(charset);


This is problematic IMO in that it's missing short strings such as "Claes". Average Java strings are about 32 bytes long AFAICR, and people writing (vectorized) ijntrinsics have a nasty habit of optimizing for long strings, to the detriment of typical-length ones.
Whether we like it or not, people will optimize for benchmarks, so it's important that benchmark data is realistic. The shortest here is 15 bytes, as far as I can see. I'd certainly include a short string of just a few bytes so that intrinsics don't cause regressions in important cases.

All good points. I've added a number of such short variants to all(?) relevant microbenchmarks. The tests should now better cover a mix of input lengths and encodings.

…e methods

openjdk · 2022-02-25T17:45:36Z

@cl4es This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8282047: Enhance StringDecode/Encode microbenchmarks

Reviewed-by: bchristi

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 87 new commits pushed to the master branch:

e96c599: 8271232: JFR: Scrub recording data
735e86b: 8282345: handle latest VS2022 in abstract_vm_version
b96b743: 8281015: Further simplify NMT backend
9471f24: 8280684: JfrRecorderService failes with guarantee(num_written > 0) when no space left on device.
3efd6aa: 8282347: AARCH64: Untaken branch in has_negatives stub
cd36be4: 8206187: javax/management/remote/mandatory/connection/DefaultAgentFilterTest.java fails with Port already in use
bf19fc6: 8280357: user.home = "?" when running with systemd DynamicUser=true
b6843a1: 8005885: enhance PrintCodeCache to print more data
23995f8: 8281525: Enable Zc:strictStrings flag in Visual Studio build
20e78f7: 8282307: Parallel: Incorrect discovery mode in PCReferenceProcessor
... and 77 more: https://git.openjdk.java.net/jdk/compare/b4900b1298e536c0ceaa77bc0ac0e8e6ccba6400...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

cl4es · 2022-03-01T10:19:39Z

/integrate

openjdk · 2022-03-01T10:20:34Z

Going to push as commit d4d12ad.
Since your change was applied there have been 109 commits pushed to the master branch:

22b93a3: 8282094: [REDO] Parallel: Refactor PSCardTable::scavenge_contents_parallel
d3022f8: 8282467: add extra diagnostics for JDK-8268184
e4d9fc8: 8282023: PropertiesStoreTest and StoreReproducibilityTest jtreg failures due to en_CA locale
c1a28aa: 8282392: [zero] Build broken on AArch64
7743266: 8281210: Add manpage changes for PAC-RET protection on Linux/AArch64
1f89acd: 8282464: Remove author tags from java.compiler
9d9618a: 8282462: Remove unnecessary use of @SuppressWarnings("preview")
d983d10: 8275731: CDS archived enums objects are recreated at runtime
c7cd148: 8282240: Add _name field to Method for NOT_PRODUCT only
59b3ecc: 8277976: Break up SEQUENCE in X509Certificate::getSubjectAlternativeNames and X509Certificate::getIssuerAlternativeNames in otherName
... and 99 more: https://git.openjdk.java.net/jdk/compare/b4900b1298e536c0ceaa77bc0ac0e8e6ccba6400...master

Your commit was automatically rebased without conflicts.

openjdk · 2022-03-01T10:20:51Z

@cl4es Pushed as commit d4d12ad.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

cl4es added 3 commits February 17, 2022 15:26

Enhance StringDecode/Encode micros

01cc39c

Drop encodeAsciiCharsetName, align names

cca2c78

Add inputs with only latin1 and UTF16 codepoints

dcad02b

Rearrange and align names

54e62ed

openjdk bot added the rfr Pull request is ready for review label Feb 17, 2022

openjdk bot added the core-libs core-libs-dev@openjdk.org label Feb 17, 2022

cl4es added a commit to cl4es/jdk that referenced this pull request Feb 17, 2022

Revert micro changes, split out to openjdk#7516

531139a

bchristi-git suggested changes Feb 24, 2022

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Brent review

0dd0449

theRealAph reviewed Feb 25, 2022

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cl4es added 2 commits February 25, 2022 10:57

Increase coverage of and weight of short strings

183f628

Fix typos, add missing short variants to latin1 and utf16 short decod…

fc2a5b0

…e methods

bchristi-git approved these changes Feb 25, 2022

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openjdk bot added the ready Pull request is ready to be integrated label Feb 25, 2022

openjdk bot added the integrated Pull request has been integrated label Mar 1, 2022

openjdk bot closed this Mar 1, 2022

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Mar 1, 2022

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