8294437: java/nio/channels/FileChannel tests slow on Windows #10464

djelinski · 2022-09-28T10:58:43Z

Please review this test-only change that improves the execution speed of a few FileChannel tests:

Transfer2GPlus, Transfer4GBFile, and TransferTo6GBFile were modified to use sparse files. Their speed is now consistent across platforms, provided that the platform / filesystem supports sparse files.
LargeMapTest was rewritten to use sparse files, and to more precisely target the issue it was written to detect. In my tests it still crashed with EXCEPTION_ACCESS_VIOLATION when JDK-8286637 was reverted.
MapTest: repetition was removed from testForce method; I'm not sure what issues it was supposed to catch, but at far as I can tell, it was only triggering timeouts, see JDK-8289526, JDK-8224480

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Issue

JDK-8294437: java/nio/channels/FileChannel tests slow on Windows

Reviewers

Alan Bateman (@AlanBateman - Reviewer) ⚠️ Review applies to 0f22fb54
Brian Burkhalter (@bplb - Reviewer) ⚠️ Review applies to 0f22fb54

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Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk pull/10464/head

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bridgekeeper · 2022-09-28T11:01:06Z

👋 Welcome back djelinski! 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 · 2022-09-28T11:03:42Z

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

nio

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mlbridge · 2022-09-28T11:20:53Z

Webrevs

AlanBateman

Creating the files as sparse files make sense, we probably should have changed these tests a long time ago.

AlanBateman · 2022-09-28T18:58:54Z

test/jdk/java/nio/channels/FileChannel/Transfer2GPlus.java

-        raf.write(b);
-        return b;
+        try (FileChannel fc = FileChannel.open(src, StandardOpenOption.CREATE_NEW,
+                StandardOpenOption.SPARSE, StandardOpenOption.WRITE)) {


LargeMapFile uses import static java.nio.file.StandardOpenOption.* which makes it easier to fit the open options on the same line.

AlanBateman · 2022-09-28T19:01:14Z

test/jdk/java/nio/channels/FileChannel/LargeMapTest.java

+        ByteBuffer bb;
+        try (FileChannel fc = FileChannel.open(p, CREATE_NEW, SPARSE, WRITE)) {
+            fc.position(BASE);
+            Random r = new Random(System.nanoTime());


It might not matter here but we usually use RandomFactory to allow for reproducibility in the event of test failure.

Thanks for the hint! It shouldn't matter here, but I'll change it.

AlanBateman · 2022-09-28T19:01:45Z

test/jdk/java/nio/channels/FileChannel/MapTest.java

-            out.println("Exceptions: OK");
+            t1 = System.nanoTime();
+            out.printf("Exceptions: done in %d ns (%d ms) %n",
+                    t1 - t0, TimeUnit.NANOSECONDS.toMillis(t1 - t0));


Are you planning to leave all these timestamps in the output? I can't tell if they are left over from your testing or intentional.

Yeah, I wanted to leave them here; they don't take up much space, and are very useful when trying to figure out why the tests are slow.

bplb · 2022-09-28T19:49:55Z

Overall I don’t see any problems aside from the copyright years which I assume you will fix before integrating. It’s good that you removed RandomAccessFile in one place. It might be good to try to remove all java.io uses where possible, e.g., not deleteOnExit(). Also, instead of creating a temporary file and then deleting it, maybe something else could be done. For example, creating a temporary directory and then creating a file with a hard-coded name within it. Or using Random to create a file name and using the REPLACE_EXISTING open option. Another thought would be to add a method createSparseTempFile() or something to lib/util/FileUtils.

djelinski · 2022-09-29T14:47:55Z

I went with adding FileUtils.createSparseTempFile(); the method implementation is still ugly, but at least it's not visible when looking at the tests.

I added one more modification to Transfer2GPlus; noticed that testToWritableByteChannel doesn't need to write to disk, and modified the code to take advantage of that; it's much faster now.

AlanBateman · 2022-09-29T15:06:14Z

I went with adding FileUtils.createSparseTempFile(); the method implementation is still ugly, but at least it's not visible when looking at the tests.

I would prefer if the FileChannel tests do not use this. The reason is that these are tests for FileChannel and should not be dependent on test infrastructure that it out of sight. It would be okay for non-FileChannel tests to use of course.

djelinski · 2022-09-29T15:11:24Z

... should not be dependent on test infrastructure that it out of sight.

would it be okay if I moved the method to, say, FileChannelUtils in FileChannel directory?

test/jdk/java/nio/channels/FileChannel/LargeMapTest.java

bplb · 2022-09-29T23:59:04Z

test/jdk/java/nio/channels/FileChannel/Transfer2GPlus.java

+             WritableByteChannel wbc = Channels.newChannel(os)){
+
+            long n;
+            if ((n = srcCh.transferTo(0, LENGTH, wbc)) < LENGTH)


The contract of FileChannel::transferTo does not guarantee that all bytes are transferred:

An invocation of this method may or may not transfer all of the requested bytes [...].

preexisting, and unlikely to change because of Hyrum's law. I can file a ticket to update the docs if you think it makes sense.

No, I think the docs should be left as they are.

Ack that. If that's okay with you, I'd rather not change this code here; it was always like that, and I haven't found any related failure reports. The tests continue to pass.

bplb · 2022-09-30T00:03:30Z

test/jdk/java/nio/channels/FileChannel/Transfer4GBFile.java

-                sinkChannel.close();
+        try (FileChannel sourceChannel = FileChannel.open(source, StandardOpenOption.READ);
+             FileChannel sinkChannel = FileChannel.open(sink, StandardOpenOption.WRITE)) {
+            long bytesWritten = sinkChannel.transferFrom(sourceChannel,


Same comment as for FileChannel::transferTo:

An invocation of this method may or may not transfer all of the requested bytes.

test/jdk/java/nio/channels/FileChannel/Transfer4GBFile.java

AlanBateman

I think this version looks okay and probably okay drop the loop from testForce. It's probably best to wait until @bplb gets to see the updated version as he has been doing most of the work in this area recently.

test/jdk/java/nio/channels/FileChannel/TransferTo6GBFile.java

openjdk · 2022-09-30T11:14:44Z

@djelinski 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:

8294437: java/nio/channels/FileChannel tests slow on Windows

Reviewed-by: alanb, bpb

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 81 new commits pushed to the master branch:

e137f9f: 8293877: Rewrite MineField test
4f44fd6: 8237467: jlink plugin to save the argument files as input to jlink in the output image
edfb18a: 8294695: Remove redundant deprecation suppression in ThreadGroup
46633e6: 8294698: Remove unused 'checkedExceptions' param from MethodAccessorGenerator.generateMethod()
f2a32d9: 8293691: converting a defined BasicType value to a string should not crash the VM
ccc1d31: 8294529: IGV: Highlight the current graphs in the Outline
08a7ecf: 8294671: Remove unused CardValues::last_card
5fe837a: 8294236: [IR Framework] CPU preconditions are overriden by regular preconditions
8e9cfeb: 8294431: jshell reports error on initialisation of static final field of anonymous class
6e8f038: 8294567: IGV: IllegalStateException in search
... and 71 more: https://git.openjdk.org/jdk/compare/dd51f7e0b75d3a16403608d89cd206ac0bedf882...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.

AlanBateman

Thanks for the update, I don't have any other comments. Will be good to get this change in as these tests are so slow on Windows right now.

bplb · 2022-10-03T16:20:19Z

test/jdk/java/nio/channels/FileChannel/TransferTo6GBFile.java

-                        throw new RuntimeException("Premature EOF!");
-                    nread += n;
-                }
+            // Setup looback connection and echo server


"looback" -> "loopback"

djelinski · 2022-10-03T17:35:43Z

Typo fixed.

Thanks for the reviews!

/integrate

openjdk · 2022-10-03T17:43:28Z

Going to push as commit a4f2078.
Since your change was applied there have been 82 commits pushed to the master branch:

c6e3daa: 8242115: C2 SATB barriers are not safepoint-safe
e137f9f: 8293877: Rewrite MineField test
4f44fd6: 8237467: jlink plugin to save the argument files as input to jlink in the output image
edfb18a: 8294695: Remove redundant deprecation suppression in ThreadGroup
46633e6: 8294698: Remove unused 'checkedExceptions' param from MethodAccessorGenerator.generateMethod()
f2a32d9: 8293691: converting a defined BasicType value to a string should not crash the VM
ccc1d31: 8294529: IGV: Highlight the current graphs in the Outline
08a7ecf: 8294671: Remove unused CardValues::last_card
5fe837a: 8294236: [IR Framework] CPU preconditions are overriden by regular preconditions
8e9cfeb: 8294431: jshell reports error on initialisation of static final field of anonymous class
... and 72 more: https://git.openjdk.org/jdk/compare/dd51f7e0b75d3a16403608d89cd206ac0bedf882...master

Your commit was automatically rebased without conflicts.

openjdk · 2022-10-03T17:44:42Z

@djelinski Pushed as commit a4f2078.

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

djelinski added 6 commits September 27, 2022 16:56

Test2g: write sparse file

bccd66c

Test6g: use sparse file

3519167

Test4g: use sparse files

c02df12

LargeMapTest: use sparse file

c63df6a

Simplify LargeMapTest

6f3b16f

MapTest: avoid costly repetition

51b50f4

openjdk bot changed the title ~~8294437~~ 8294437: java/nio/channels/FileChannel tests slow on Windows Sep 28, 2022

openjdk bot added the nio nio-dev@openjdk.org label Sep 28, 2022

djelinski marked this pull request as ready for review September 28, 2022 11:15

openjdk bot added the rfr Pull request is ready for review label Sep 28, 2022

AlanBateman reviewed Sep 28, 2022

View reviewed changes

djelinski added 7 commits September 29, 2022 10:13

Update copyright year

f902c5c

Use RandomFactory to generate random bytes

b45761e

Implement createSparseTempFile

6804df7

Migrate Transfer4GBFile to nio

d61864d

rewrite testToWritableByteChannel without using file output

9f46d59

reintroduce deleteOnExit

aa3fbd8

Remove intermittently failing deletes

614d0e5

bplb reviewed Sep 29, 2022

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test/jdk/java/nio/channels/FileChannel/LargeMapTest.java Show resolved Hide resolved

bplb reviewed Sep 29, 2022

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bplb reviewed Sep 30, 2022

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test/jdk/java/nio/channels/FileChannel/Transfer4GBFile.java Outdated Show resolved Hide resolved

Import static StandardOpenOption

6c83a2b

djelinski added 3 commits September 30, 2022 09:01

add randomness

66f22dd

Move createSparseTempFile closer to FileChannel

0af8763

Add explicit build tags

08829f0

openjdk bot removed the rfr Pull request is ready for review label Sep 30, 2022

Fix file attributes

a8a28f1

openjdk bot added the rfr Pull request is ready for review label Sep 30, 2022

AlanBateman approved these changes Sep 30, 2022

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test/jdk/java/nio/channels/FileChannel/TransferTo6GBFile.java Outdated Show resolved Hide resolved

openjdk bot added the ready Pull request is ready to be integrated label Sep 30, 2022

Use try with resources

0f22fb5

AlanBateman approved these changes Oct 1, 2022

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bplb reviewed Oct 3, 2022

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bplb approved these changes Oct 3, 2022

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Fix typo

148ea2c

openjdk bot added the integrated Pull request has been integrated label Oct 3, 2022

openjdk bot closed this Oct 3, 2022

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Oct 3, 2022

djelinski deleted the filechannel-tests branch October 3, 2022 19:11

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8294437: java/nio/channels/FileChannel tests slow on Windows #10464

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8294437: java/nio/channels/FileChannel tests slow on Windows #10464

8294437: java/nio/channels/FileChannel tests slow on Windows #10464

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