8283199: Linux os::cpu_microcode_revision() stalls cold startup

[shipilev]

Unclean backport to fix the startup time regression.

The backport is not clean, because JDK-8238161 is not present in JDK 17, and thus we have fopen instead of os::fopen in these hunks. I changed the code back to fopen to be consistent with the rest of JDK 17.

Verified the startup time improves, using the scripts from the issue.

# Before
real	0m0.042s
real	0m0.043s
real	0m0.043s

# After
real	0m0.025s
real	0m0.024s
real	0m0.024s

Additional testing:

• Linux x86_64 fastdebug tier1

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8283199: Linux os::cpu_microcode_revision() stalls cold startup

Reviewers

• Thomas Stuefe (@tstuefe - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk17u-dev pull/820/head:pull/820
$ git checkout pull/820

Update a local copy of the PR:
$ git checkout pull/820
$ git pull https://git.openjdk.org/jdk17u-dev pull/820/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 820

View PR using the GUI difftool:
$ git pr show -t 820

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk17u-dev/pull/820.diff

[bridgekeeper]

👋 Welcome back shade! 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]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (a4c358c9)

[shipilev]

Any takers? :)

[tstuefe]

All good.

[openjdk]

@shipilev 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:

8283199: Linux os::cpu_microcode_revision() stalls cold startup

Reviewed-by: stuefe

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 44 new commits pushed to the master branch:

• 3a5bcf0: 8281744: x86: Use short jumps in TIG::set_vtos_entry_points
• a00bd13: 8279941: sun/security/pkcs11/Signature/TestDSAKeyLength.java fails when NSS version detection fails
• a61b74e: 8272608: java_lang_System::allow_security_manager() doesn't set its initialization flag
• 18c4c25: 8277970: Test jdk/sun/security/ssl/SSLSessionImpl/NoInvalidateSocketException.java fails with "tag mismatch"
• 21c52e3: 8290920: sspi_bridge.dll not built if BUILD_CRYPTO is false
• d38a343: 8295554: Move the "sizecalc.h" to the correct location
• ff14ed4: 8292695: SIGQUIT and jcmd attaching mechanism does not work with signal chaining library
• f2a10fd: 8265489: Stress test times out because of long ObjectSynchronizer::monitors_iterate(...) operation
• 092be50: 8287740: NSAccessibilityShowMenuAction not working for text editors
• b37d7df: 8275569: Add linux-aarch64 to test-make profiles
• ... and 34 more: https://git.openjdk.org/jdk17u-dev/compare/fe4819b5eb25e97b459aded9e1ab93586445b301...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.

[shipilev]

All good.

Thanks! I marked the issue for approval.

[shipilev]

Got the push approval.

/integrate

[openjdk]

Going to push as commit 6196d93.
Since your change was applied there have been 44 commits pushed to the master branch:

• 3a5bcf0: 8281744: x86: Use short jumps in TIG::set_vtos_entry_points
• a00bd13: 8279941: sun/security/pkcs11/Signature/TestDSAKeyLength.java fails when NSS version detection fails
• a61b74e: 8272608: java_lang_System::allow_security_manager() doesn't set its initialization flag
• 18c4c25: 8277970: Test jdk/sun/security/ssl/SSLSessionImpl/NoInvalidateSocketException.java fails with "tag mismatch"
• 21c52e3: 8290920: sspi_bridge.dll not built if BUILD_CRYPTO is false
• d38a343: 8295554: Move the "sizecalc.h" to the correct location
• ff14ed4: 8292695: SIGQUIT and jcmd attaching mechanism does not work with signal chaining library
• f2a10fd: 8265489: Stress test times out because of long ObjectSynchronizer::monitors_iterate(...) operation
• 092be50: 8287740: NSAccessibilityShowMenuAction not working for text editors
• b37d7df: 8275569: Add linux-aarch64 to test-make profiles
• ... and 34 more: https://git.openjdk.org/jdk17u-dev/compare/fe4819b5eb25e97b459aded9e1ab93586445b301...master

Your commit was automatically rebased without conflicts.

[openjdk]

@shipilev Pushed as commit 6196d93.

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