8269559: AArch64: Implement string_compare intrinsic in SVE #5129

tatwaichong · 2021-08-16T20:59:55Z

This patch implements string_compare intrinsic in SVE.
It supports all LL, LU, UL and UU comparisons.

As we haven't found an existing benchmark to measure performance impact,
we created a benchmark derived from the test [1] for this evaluation.
This benchmark is attached to this patch.

Besides, remove the unused temporary register vtmp3 from the existing
match rules for StrCmp.

The result below shows all varients can be benefited largely.
Command: make exploded-test TEST="micro:StringCompareToDifferentLength"

Benchmark (size) Mode Cnt Score Speedup Units
compareToLL 24 avgt 10 1.0x ms/op
compareToLL 36 avgt 10 1.0x ms/op
compareToLL 72 avgt 10 1.0x ms/op
compareToLL 128 avgt 10 1.4x ms/op
compareToLL 256 avgt 10 1.8x ms/op
compareToLL 512 avgt 10 2.7x ms/op
compareToLU 24 avgt 10 1.6x ms/op
compareToLU 36 avgt 10 1.8x ms/op
compareToLU 72 avgt 10 2.3x ms/op
compareToLU 128 avgt 10 3.8x ms/op
compareToLU 256 avgt 10 4.7x ms/op
compareToLU 512 avgt 10 6.3x ms/op
compareToUL 24 avgt 10 1.6x ms/op
compareToUL 36 avgt 10 1.7x ms/op
compareToUL 72 avgt 10 2.2x ms/op
compareToUL 128 avgt 10 3.3x ms/op
compareToUL 256 avgt 10 4.4x ms/op
compareToUL 512 avgt 10 6.1x ms/op
compareToUU 24 avgt 10 1.0x ms/op
compareToUU 36 avgt 10 1.0x ms/op
compareToUU 72 avgt 10 1.4x ms/op
compareToUU 128 avgt 10 2.2x ms/op
compareToUU 256 avgt 10 2.6x ms/op
compareToUU 512 avgt 10 3.7x ms/op

[1] https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/intrinsics/string/TestStringCompareToDifferentLength.java

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Issue

JDK-8269559: AArch64: Implement string_compare intrinsic in SVE

Reviewers

Nick Gasson (@nick-arm - Reviewer) ⚠️ Review applies to 2ae102d
Andrew Haley (@theRealAph - Reviewer) ⚠️ Review applies to 2ae102d

Reviewing

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Checkout this PR locally:
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$ git checkout pull/5129

Update a local copy of the PR:
$ git checkout pull/5129
$ git pull https://git.openjdk.java.net/jdk pull/5129/head

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Checkout this PR locally:
$ git pr checkout 5129

View PR using the GUI difftool:
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https://git.openjdk.java.net/jdk/pull/5129.diff

This patch implements string_compare intrinsic in SVE. It supports all LL, LU, UL and UU comparisons. As we haven't found an existing benchmark to measure performance impact, we created a benchmark derived from the test [1] for this evaluation. This benchmark is attached to this patch. Besides, remove the unused temporary register `vtmp3` from the existing match rules for StrCmp. The result below shows all varients can be benefited largely. Command: make exploded-test TEST="micro:StringCompareToDifferentLength" Benchmark (size) Mode Cnt Score Speedup Units compareToLL 24 avgt 10 1.0x ms/op compareToLL 36 avgt 10 1.0x ms/op compareToLL 72 avgt 10 1.0x ms/op compareToLL 128 avgt 10 1.4x ms/op compareToLL 256 avgt 10 1.8x ms/op compareToLL 512 avgt 10 2.7x ms/op compareToLU 24 avgt 10 1.6x ms/op compareToLU 36 avgt 10 1.8x ms/op compareToLU 72 avgt 10 2.3x ms/op compareToLU 128 avgt 10 3.8x ms/op compareToLU 256 avgt 10 4.7x ms/op compareToLU 512 avgt 10 6.3x ms/op compareToUL 24 avgt 10 1.6x ms/op compareToUL 36 avgt 10 1.7x ms/op compareToUL 72 avgt 10 2.2x ms/op compareToUL 128 avgt 10 3.3x ms/op compareToUL 256 avgt 10 4.4x ms/op compareToUL 512 avgt 10 6.1x ms/op compareToUU 24 avgt 10 1.0x ms/op compareToUU 36 avgt 10 1.0x ms/op compareToUU 72 avgt 10 1.4x ms/op compareToUU 128 avgt 10 2.2x ms/op compareToUU 256 avgt 10 2.6x ms/op compareToUU 512 avgt 10 3.7x ms/op [1] https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/intrinsics/string/TestStringCompareToDifferentLength.java

bridgekeeper · 2021-08-16T21:00:22Z

👋 Welcome back tatwaichong! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2021-08-16T21:03:55Z

@tatwaichong The following labels will be automatically applied to this pull request:

core-libs
hotspot-compiler

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

mlbridge · 2021-08-16T21:09:55Z

Webrevs

nick-arm · 2021-08-17T07:14:24Z

src/hotspot/cpu/aarch64/aarch64.ad

  %}
  ins_pipe(pipe_class_memory);
 %}

 instruct string_compareUL(iRegP_R1 str1, iRegI_R2 cnt1, iRegP_R3 str2, iRegI_R4 cnt2,
                        iRegI_R0 result, iRegP_R10 tmp1, iRegL_R11 tmp2,
-                        vRegD_V0 vtmp1, vRegD_V1 vtmp2, vRegD_V2 vtmp3, rFlagsReg cr)


I think vtmp3 (=V2) is still used by the non-SVE compare-long-strings stub? (see generate_compare_long_string_different_encoding)

Thanks, Nick.
Yes. I remove this vtmp3 from input arguments wrongly. I roll back this mistake in the following patch.

… compare-long-strings stub. And remove the assertion in `string_compare` since it won't help as the registers used in the stub are fixed.

nick-arm

This looks ok to me now but please wait to see if @theRealAph has any comments. I suppose the the short-string comparison code which is expanded at the call site could also benefit from SVE, if only to make it shorter.

openjdk · 2021-08-24T04:19:40Z

@tatwaichong 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:

8269559: AArch64: Implement string_compare intrinsic in SVE

Reviewed-by: ngasson, aph

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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential automatic rebasing, please check the documentation for the /integrate command for further details.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@nick-arm, @theRealAph) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

bridgekeeper · 2021-09-21T04:52:35Z

@tatwaichong This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

tatwaichong · 2021-09-28T02:02:29Z

@theRealAph Hello, Andrew. I'm wondering are you interested in reviewing this patch? I believe your feedback and comment are useful to it.

openjdk · 2021-09-30T10:16:11Z

@tatwaichong this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout sve_compareto
git fetch https://git.openjdk.java.net/jdk master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

tatwaichong · 2021-10-14T04:10:45Z

/integrate

openjdk · 2021-10-14T04:11:41Z

@tatwaichong
Your change (at version 7799f93) is now ready to be sponsored by a Committer.

nick-arm · 2021-10-14T05:25:53Z

/sponsor

openjdk · 2021-10-14T05:27:23Z

Going to push as commit 8b1b6f9.

openjdk · 2021-10-14T05:27:39Z

@nick-arm @tatwaichong Pushed as commit 8b1b6f9.

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

mlbridge · 2021-10-14T06:14:20Z

Mailing list message from David Holmes on core-libs-dev:

We are seeing a large number of Aarch64 test failures in our CI after
this push. Somewhat bizarre failure modes:
- truncated classfiles
- unexpected EOF encountered
- illegal state reading a stream

I think we will need to back this change out while this is investigated
further.

David
-----

On 14/10/2021 3:30 pm, TatWai Chong wrote:

nick-arm · 2021-10-14T06:26:04Z

Hm, I didn't see anything like that when we tested this patch internally. I'll create another PR to revert it for now.

mlbridge · 2021-10-14T06:40:20Z

Mailing list message from David Holmes on core-libs-dev:

On 14/10/2021 4:28 pm, Nick Gasson wrote:

On Thu, 14 Oct 2021 01:17:17 GMT, TatWai Chong <duke at openjdk.java.net> wrote:

This patch implements string_compare intrinsic in SVE.
It supports all LL, LU, UL and UU comparisons.

As we haven't found an existing benchmark to measure performance impact,
we created a benchmark derived from the test [1] for this evaluation.
This benchmark is attached to this patch.

Besides, remove the unused temporary register `vtmp3` from the existing
match rules for StrCmp.

The result below shows all varients can be benefited largely.
Command: make exploded-test TEST="micro:StringCompareToDifferentLength"

Benchmark (size) Mode Cnt Score Speedup Units
compareToLL 24 avgt 10 1.0x ms/op
compareToLL 36 avgt 10 1.0x ms/op
compareToLL 72 avgt 10 1.0x ms/op
compareToLL 128 avgt 10 1.4x ms/op
compareToLL 256 avgt 10 1.8x ms/op
compareToLL 512 avgt 10 2.7x ms/op
compareToLU 24 avgt 10 1.6x ms/op
compareToLU 36 avgt 10 1.8x ms/op
compareToLU 72 avgt 10 2.3x ms/op
compareToLU 128 avgt 10 3.8x ms/op
compareToLU 256 avgt 10 4.7x ms/op
compareToLU 512 avgt 10 6.3x ms/op
compareToUL 24 avgt 10 1.6x ms/op
compareToUL 36 avgt 10 1.7x ms/op
compareToUL 72 avgt 10 2.2x ms/op
compareToUL 128 avgt 10 3.3x ms/op
compareToUL 256 avgt 10 4.4x ms/op
compareToUL 512 avgt 10 6.1x ms/op
compareToUU 24 avgt 10 1.0x ms/op
compareToUU 36 avgt 10 1.0x ms/op
compareToUU 72 avgt 10 1.4x ms/op
compareToUU 128 avgt 10 2.2x ms/op
compareToUU 256 avgt 10 2.6x ms/op
compareToUU 512 avgt 10 3.7x ms/op

[1] https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/intrinsics/string/TestStringCompareToDifferentLength.java

TatWai Chong has updated the pull request incrementally with one additional commit since the last revision:

Replace `sve_cmpne` with up-to-date `sve_cmp`.

Hm, I didn't see anything like that when we tested this patch internally. I'll create another PR to revert it for now.

Filed: https://bugs.openjdk.java.net/browse/JDK-8275263

If a backout is needed then it should be converted to a "backout" issue per:

https://openjdk.java.net/guide/index.html#backing-out-a-change

Thanks,
David

openjdk bot added the rfr label Aug 16, 2021

openjdk bot added hotspot-compiler core-libs labels Aug 16, 2021

nick-arm reviewed Aug 17, 2021

View changes

Restore the removal of vtmp3 (=V2) as it is still used by the non-SVE…

2ae102d

… compare-long-strings stub. And remove the assertion in `string_compare` since it won't help as the registers used in the stub are fixed.

nick-arm approved these changes Aug 24, 2021

View changes

openjdk bot added the ready label Aug 24, 2021

wuyan0 mentioned this pull request Aug 26, 2021

8268231: Aarch64: Use ldp in intrinsics for String.compareTo #4722

Closed

3 tasks

theRealAph approved these changes Sep 30, 2021

View changes

openjdk bot added merge-conflict and removed ready labels Sep 30, 2021

Merge master

4a58408

openjdk bot added ready and removed merge-conflict labels Oct 13, 2021

Replace sve_cmpne with up-to-date sve_cmp.

7799f93

openjdk bot added the sponsor label Oct 14, 2021

openjdk bot closed this Oct 14, 2021

openjdk bot added the integrated label Oct 14, 2021

openjdk bot removed ready rfr sponsor labels Oct 14, 2021

tatwaichong mentioned this pull request Nov 4, 2021

8275448: [REDO] AArch64: Implement string_compare intrinsic in SVE #6072

Closed

3 tasks

Wanghuang-Huawei mentioned this pull request Jan 10, 2022

8279560: AArch64: generate_compare_long_string_same_encoding and LARGE_LOOP_PREFETCH alignment #7007

Closed

3 tasks

8269559: AArch64: Implement string_compare intrinsic in SVE #5129

8269559: AArch64: Implement string_compare intrinsic in SVE #5129

tatwaichong commented Aug 16, 2021 •

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8269559: AArch64: Implement string_compare intrinsic in SVE #5129

8269559: AArch64: Implement string_compare intrinsic in SVE #5129

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tatwaichong commented Aug 16, 2021 • edited by openjdk[bot] bot

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