To build and run the JMH benchmark, ensure Maven is installed (the mvn command should be available in the shell). On Ubuntu, this is as easy as running sudo apt install maven then setting up JMH using the steps below.
git clone https://github.com/swesonga/benchmarks
cd benchmarks
cd java/jmh
./setup_jmh_jdk_micros.sh
./run_jmh_jdk_micros.sh Parallel 1 2 10 5 5
The setup_jmh_jdk_micros.sh script builds the JMH JDK microbenchmarks and the run_jmh_jdk_micros.sh run the benchmark. Someone recently asked why there are 2 java processes shown in top when the run_jmh_jdk_micros.sh script runs given that it launches only 1 java process. I learned from this site how to use top to see java processes only: run top, type ‘o’, then type ‘COMMAND=java’ and press ENTER. This is the resulting output from the top command:
top - 22:15:21 up 8:15, 1 user, load average: 1.73, 0.66, 0.30
Tasks: 330 total, 1 running, 329 sleeping, 0 stopped, 0 zombie
%Cpu(s): 20.9 us, 0.6 sy, 0.0 ni, 78.3 id, 0.0 wa, 0.0 hi, 0.2 si, 0.0 st
MiB Mem : 15415.5 total, 5837.9 free, 5436.0 used, 4141.6 buff/cache
MiB Swap: 2048.0 total, 2048.0 free, 0.0 used. 9568.6 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
22007 saint 20 0 5009436 1.1g 22464 S 345.3 7.2 1:02.74 java
21927 saint 20 0 5607592 1.1g 23100 S 0.3 7.2 0:01.08 java
Sure enough, there are 2 java processes, each with 1.1g RES. This can also be confirmed by running the ps -aux | grep java command.
Notice that one of the processes has an IP address and what is most likely a port number. Without knowing anything else, this would suggest a client/server model in use. To better understand why there are 2 java processes, let us see look at how the run script launches Java. It passes flags like -f 1 to the benchmark jar file. What parses these flags?
The benchmark JAR file is created from a pom.xml file containing a mainClass attribute of org.openjdk.jmh.Main. That’s the class responsible for parsing these flags. This Main class uses the CommandLineOptions class to parse arguments like -f 1 then executes the Runner.run() method. Runner.runBenchmarks() checks whether the benchmarks should be run embedded or forked. runBenchmarksEmbedded() has a warning about using non-forked runs only for debugging purposes. This answers the question of why there are 2 JVMs: we are running in forked mode. runSeparate() has a getForkedMainCommand() method, which suggests that there is most likely a way to pass custom arguments to the ForkedMain JVM.
Now that we understand why there are 2 JVMs, can we control the heap size of each of them independently? The CommandLineOptions class has a list of all the supported arguments. Notice the jvmArgs, jvmArgsAppend, and jvmArgsAppend arguments! These suggest that we can indeed control the heap sizes of each of the JVMs. Use the jvmArgsAppend flag in the run_jmh_jdk_micros.sh script (e.g. just before the benchmark_filter_regex to specify a custom heap size for the forked java process (independent of the jvm_heap_size_opts).
Installing Maven
I did not have Java set up on my Ubuntu VM. Therefore, setting up MVN installed Java and many other dependencies. I decided to list these here for future reference.
saint@vm1ubuntu:~/java$ sudo apt install maven
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
ca-certificates-java default-jre-headless java-common libaopalliance-java libapache-pom-java libatinject-jsr330-api-java libcdi-api-java libcommons-cli-java
libcommons-io-java libcommons-lang3-java libcommons-parent-java libgeronimo-annotation-1.3-spec-java libgeronimo-interceptor-3.0-spec-java libguava-java
libguice-java libhawtjni-runtime-java libjansi-java libjansi-native-java libjsr305-java libmaven-parent-java libmaven-resolver-java libmaven-shared-utils-java
libmaven3-core-java libplexus-cipher-java libplexus-classworlds-java libplexus-component-annotations-java libplexus-interpolation-java libplexus-sec-dispatcher-java
libplexus-utils2-java libsisu-inject-java libsisu-plexus-java libslf4j-java libwagon-file-java libwagon-http-shaded-java libwagon-provider-api-java
openjdk-11-jre-headless
Suggested packages:
default-jre libaopalliance-java-doc libatinject-jsr330-api-java-doc libel-api-java libcommons-io-java-doc libcommons-lang3-java-doc libasm-java libcglib-java
libjsr305-java-doc libmaven-shared-utils-java-doc liblogback-java libplexus-classworlds-java-doc libplexus-sec-dispatcher-java-doc libplexus-utils2-java-doc junit4
testng libcommons-logging-java liblog4j1.2-java fonts-dejavu-extra fonts-ipafont-gothic fonts-ipafont-mincho fonts-wqy-microhei | fonts-wqy-zenhei
The following NEW packages will be installed:
ca-certificates-java default-jre-headless java-common libaopalliance-java libapache-pom-java libatinject-jsr330-api-java libcdi-api-java libcommons-cli-java
libcommons-io-java libcommons-lang3-java libcommons-parent-java libgeronimo-annotation-1.3-spec-java libgeronimo-interceptor-3.0-spec-java libguava-java
libguice-java libhawtjni-runtime-java libjansi-java libjansi-native-java libjsr305-java libmaven-parent-java libmaven-resolver-java libmaven-shared-utils-java
libmaven3-core-java libplexus-cipher-java libplexus-classworlds-java libplexus-component-annotations-java libplexus-interpolation-java libplexus-sec-dispatcher-java
libplexus-utils2-java libsisu-inject-java libsisu-plexus-java libslf4j-java libwagon-file-java libwagon-http-shaded-java libwagon-provider-api-java maven
openjdk-11-jre-headless
0 upgraded, 37 newly installed, 0 to remove and 72 not upgraded.
Need to get 52.7 MB of archives.
After this operation, 189 MB of additional disk space will be used.
Do you want to continue? [Y/n]
The build_llvm_release.bat script in the LLVM repo is used to create a release build for Windows. Running it without any arguments displays a sample command line to use to build LLVM.
cd \repos && mkdir llvmcd \repos\llvm\llvm-project\llvm\utils\release
C:\> cd \repos\llvm\llvm-project\llvm\utils\release
C:\repos\llvm\llvm-project\llvm\utils\release> build_llvm_release.bat
--version option is required
=============================
Script for building the LLVM installer on Windows,
used for the releases at https://github.com/llvm/llvm-project/releases
Usage: build_llvm_release.bat --version <version> [--x86,--x64, --arm64]
Options:
--version: [required] version to build
--help: display this help
--x86: build and test x86 variant
--x64: build and test x64 variant
--arm64: build and test arm64 variant
Note: At least one variant to build is required.
Example: build_llvm_release.bat --version 15.0.0 --x86 --x64
Let us build version 17.0.1, which is the latest LLVM release. Open an administrator Developer Command Prompt then run:
:: set PATH=%PATH%;C:\Program Files\7-Zip
build_llvm_release.bat --version 17.0.1 --x64
The first error is caused by mv not being a standard command in the Windows command prompt. There are ways to create aliases, e.g. alias – Aliases in Windows command prompt – Stack Overflow but given that this is a batch file, why not just use the built-in function? I fix this in the script.
C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_17.0.1> mv llvm-project-* llvm-project || exit /b 1
'mv' is not recognized as an internal or external command,
operable program or batch file.
The build directory needs to be deleted before restarting the build with the fix. Otherwise, the script will fail.
However, from a new command window, it looks like it hasn’t been set up.
C:\repos> python --version
Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.
Just running python loads the Microsoft Store:
I proceed with the Customize Installation option in the open Python installer, this time selecting “for all users (requires admin privileges)”.
I’m not sure why the “Install Python 3.11 for all users” option is not checked on the “Advanced Options” page.
Opening a new command prompt then running python still gives the same behavior as before. where python shows that the new installation appears 2nd.
C:\repos> where python
C:\Users\saint\AppData\Local\Microsoft\WindowsApps\python.exe
C:\Python311\python.exe
The PATH environment variable has these paths in reverse order so I don’t understand what is happening. Looks like the easiest way forward is to just install python from the Microsoft Store – this at least ensures that python scripts can run. After a failure due to the python command not being found, closer inspection of build_llvm_release.bat reveals that it needs the PYTHON_HOME environment variable to be set. However, that is set on line 358 using the python_dir variable, which is in turn the first argument to :set_environment. The call to set_environment is from :do_build_32 (or do_build_64), which uses a hard-coded python path! The script should first validate the python installation and exit early if it cannot be found! I should have reported/fixed these when I worked on Tracking Down Missing Headers in LLVM for Windows – Saint’s Log (swesonga.org) last year.
Build Errors
With the Python path fixed, the build proceeds but the C++ compilation fails. A few months ago I got the error below build version 15.0.7. Unfortunately, I didn’t explicitly note the compiler version.
FAILED: tools/clang/lib/Analysis/FlowSensitive/CMakeFiles/obj.clangAnalysisFlowSensitive.dir/HTMLLogger.cpp.obj
C:\PROGRA~1\MICROS~3\2022\COMMUN~1\VC\Tools\MSVC\1438~1.331\bin\Hostx64\x64\cl.exe /nologo /TP ... -c C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_17.0.1\llvm-project\clang\lib\Analysis\FlowSensitive\HTMLLogger.cpp
C:\repos\llvm\llvm-project\llvm\utils\release\llvm_package_17.0.1\llvm-project\clang\lib\Analysis\FlowSensitive\HTMLLogger.cpp(332): fatal error C1001: Internal compiler error.
(compiler file 'msc1.cpp', line 1587)
To work around this problem, try simplifying or changing the program near the locations listed above.
If possible please provide a repro here: https://developercommunity.visualstudio.com
Please choose the Technical Support command on the Visual C++
Help menu, or open the Technical Support help file for more information
Additional troubleshooting is obviously required to make progress here. I might try to create a narrowed down testcase for the internal compiler error or perhaps just report it as is and let the Visual C++ team figure that out.
Note: I wrote this in October 2022 but never got around to posting it. Doing so now to enable comparisons with the latest sources and compilers.
In Failing to Build Flang with Visual C++, the C++ compiler had bugs that prevented compilation from succeeding. I just tried a new version of the Visual C++ compiler (Microsoft (R) C/C++ Optimizing Compiler Version 19.34.31823.3 for x64). This failed to build the same commit with the following error.
D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1585): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1585): warning C4189: 'ctx': local variable is initialized but not referenced
...
D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1578): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\lib\Evaluate\fold-implementation.h(1578): warning C4101: 'buffer': unreferenced local variable
...
Moving that variable deeper into the if-statement addresses that issue. I end up having to suppress C4661 again.
D:\dev\repos\llvm-project\flang\include\flang\Evaluate\expression.h(101): error C2220: the following warning is treated as an error
D:\dev\repos\llvm-project\flang\include\flang\Evaluate\expression.h(101): warning C4661: 'std::optional<Fortran::evaluate::DynamicType> Fortran::evaluate::ExpressionBase<Fortran::evaluate::SomeDerived>::GetType(void) const': no suitable definition provided for explicit template instantiation request
...
C:\PROGRA~1\MIB055~1\2022\Preview\VC\Tools\MSVC\1434~1.318\bin\Hostx64\x64\cl.exe /nologo /TP -DFLANG_LITTLE_ENDIAN=1 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\unittests\Evaluate -ID:\dev\repos\llvm-project\flang\unittests\Evaluate -ID:\dev\repos\llvm-project\flang\include -ID:\dev\repos\llvm-project\build-nowarn\tools\flang\include -ID:\dev\repos\llvm-project\build-nowarn\include -ID:\dev\repos\llvm-project\llvm\include -external:ID:\dev\repos\llvm-project\llvm\..\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\mlir\include -external:ID:\dev\repos\llvm-project\build-nowarn\tools\clang\include -external:ID:\dev\repos\llvm-project\llvm\..\clang\include -external:W0 /DWIN32 /D_WINDOWS /Zc:inline /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd4661 -wd4927 -wd4324 -w14062 -we4238 /Gw /WX /MD /O2 /Ob2 -UNDEBUG -std:c++17 /showIncludes /Fotools\flang\unittests\Evaluate\CMakeFiles\FortranEvaluateTesting.dir\fp-testing.cpp.obj /Fdtools\flang\unittests\Evaluate\CMakeFiles\FortranEvaluateTesting.dir\FortranEvaluateTesting.pdb /FS -c D:\dev\repos\llvm-project\flang\unittests\Evaluate\fp-testing.cpp
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\xtree(1664): error C2220: the following warning is treated as an error
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\xtree(1626): note: see reference to function template instantiation 'std::_Tree_node<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>,std::_Default_allocator_traits<_Alloc>::void_pointer> *std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::_Copy_nodes<std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::_Strategy::_Copy>(std::_Tree_node<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>,std::_Default_allocator_traits<_Alloc>::void_pointer> *,std::_Tree_node<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>,std::_Default_allocator_traits<_Alloc>::void_pointer> *)' being compiled
with
[
_Alloc=std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>,
_Kty=Fortran::parser::CharBlock,
_Ty=Fortran::common::ConstantSubscript,
_Pr=std::less<Fortran::parser::CharBlock>
]
...
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\map(109): note: while compiling class template member function 'std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>>::map(const std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>> &)'
D:\dev\repos\llvm-project\flang\include\flang/Evaluate/common.h(243): note: see reference to function template instantiation 'std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>>::map(const std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>> &)' being compiled
D:\dev\repos\llvm-project\flang\include\flang/Evaluate/common.h(291): note: see reference to class template instantiation 'std::map<Fortran::parser::CharBlock,Fortran::common::ConstantSubscript,std::less<Fortran::parser::CharBlock>,std::allocator<std::pair<const Fortran::parser::CharBlock,Fortran::common::ConstantSubscript>>>' being compiled
C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.34.31823\include\xtree(1664): warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc
I try setting this flag just at the end of the if(MSVC) block in HandleLLVMOptions.cmake. Unfortunately, the build still fails and that’s when I notice that the earlier command lines in this post have the /EHs-c- flag. Looks like HandleLLVMOptions.cmake is explicitly removing such flags. The next logical step is to search for /EH in the codebase to see how it’s getting set for the commands that have it. That’s when I notice clang-cl – looks like a cl.exe immitation. Maybe this is how they’ve been building flang for windows without addressing all these Visual C++ issues?
Back to the exception handling issue: searching for /EHsc leads me to AddLLVM.cmake which references the LLVM_ENABLE_EH variable. Looks like that defaults to OFF in HandleLLVMOptions.cmake and it also needs LLVM_ENABLE_RTTI to be enabled.
The fact that this still doesn’t address the warning is the red flag forcing me to notice that this is a unit test and we probably don’t want to turn on RTTI anyway. That would be a huge change! Let’s drop these flags and instead modify the flang/unittests/CMakeLists.txt to add the -EHsc flag. That turns out to be exactly the right fix! Building with this command line takes about 1hr 55min on my desktop.
At this point, the commit I’ve been using and the Visual Studio build (17.4.0 Preview 3 with C++ compiler version 19.34.31823.3) are outdated. Let’s see what happens with the latest code and Visual Studio 17.4.0 Preview 4 (with C++ compiler version 19.34.31931). Bad timing on my part though, the installer now says Preview 5.0 is available and it comes with Microsoft (R) C/C++ Optimizing Compiler Version 19.34.31932 for x86. Not sure why these new preview builds are showing the x86 host when launching the developer command prompt from the start menu. Doesn’t happen when using the drop down in Windows Terminal.
To change the active code page, go to Control Panel > Region. Click on the “Change system locale…” button in the Administrative tab.
The Region Dialog Box
The Region Settings dialog will pop up. Select a different locale e.g. Japanese (Japan).
Reboot when prompted. You can verify (even before rebooting) that the active and OEM code pages have changed. Locales like Kiswahili (Kenya) and English (India) did not change the code page values (and therefore didn’t prompt to reboot).
After rebooting, I delete the build directory then configure and build OpenJDK again. This time the build fails with these errors:
ERROR: Build failed for target 'images' in configuration 'windows-x86_64-server-slowdebug' (exit code 2)
Stopping javac server
=== Output from failing command(s) repeated here ===
* For target hotspot_variant-server_libjvm_gtest_objs_test_json.obj:
test_json.cpp
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(357): error C2143: syntax error: missing ')' before ']'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(355): error C2660: 'JSON_GTest::test': function does not take 1 arguments
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(49): note: see declaration of 'JSON_GTest::test'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(355): note: while trying to match the argument list '(const char [171])'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(357): error C2143: syntax error: missing ';' before ']'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(357): error C2059: syntax error: ']'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(357): error C2017: illegal escape sequence
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(357): error C2059: syntax error: ')'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(363): error C2143: syntax error: missing ')' before ']'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(361): error C2660: 'JSON_GTest::test': function does not take 1 arguments
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(49): note: see declaration of 'JSON_GTest::test'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(361): note: while trying to match the argument list '(const char [174])'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(363): error C2143: syntax error: missing ';' before ']'
d:\java\forks\jdk\test\hotspot\gtest\utilities\test_json.cpp(363): error C2059: syntax error: ']'
... (rest of output omitted)
* All command lines available in /cygdrive/d/java/forks/jdk/build/windows-x86_64-server-slowdebug/make-support/failure-logs.
=== End of repeated output ===
No indication of failed target found.
HELP: Try searching the build log for '] Error'.
HELP: Run 'make doctor' to diagnose build problems.
The Visual C++ compiler’s behavior when reading source files depends on whether or not source files have a byte-order mark.
By default, Visual Studio detects a byte-order mark to determine if the source file is in an encoded Unicode format, for example, UTF-16 or UTF-8. If no byte-order mark is found, it assumes that the source file is encoded in the current user code page, unless you’ve specified a code page by using /utf-8 or the /source-charset option.
This can be easily tested using hexdump in Cygwin. Launch notepad and open the test.txt file created by these commands. The File > Save as dialog has an Encoding dropdown that write a byte-order marker for any of the UTF options. Running hexdump will display the byte-order markers.
echo abc123 > test.txt
hexdump -C test.txt
Inspect the OpenJDK source file failing to build confirms that there is no BOM in the file. (can this be done on GitHub?)
diff --git a/make/autoconf/flags-cflags.m4 b/make/autoconf/flags-cflags.m4
index c0c78ce95b6..bbb0426c368 100644
--- a/make/autoconf/flags-cflags.m4
+++ b/make/autoconf/flags-cflags.m4
@@ -560,7 +560,9 @@ AC_DEFUN([FLAGS_SETUP_CFLAGS_HELPER],
TOOLCHAIN_CFLAGS_JVM="-qtbtable=full -qtune=balanced -fno-exceptions \
-qalias=noansi -qstrict -qtls=default -qnortti -qnoeh -qignerrno -qstackprotect"
elif test "x$TOOLCHAIN_TYPE" = xmicrosoft; then
- TOOLCHAIN_CFLAGS_JVM="-nologo -MD -Zc:preprocessor -Zc:strictStrings -Zc:inline -MP"
+ # The -utf8 option sets source and execution character sets to UTF-8 to enable correct
+ # compilation of all source files regardless of the active code page on Windows.
+ TOOLCHAIN_CFLAGS_JVM="-nologo -MD -Zc:preprocessor -Zc:strictStrings -Zc:inline -MP -utf-8"
TOOLCHAIN_CFLAGS_JDK="-nologo -MD -Zc:preprocessor -Zc:strictStrings -Zc:inline -Zc:wchar_t-"
fi
The build still fails but this time the error is from the java.desktop tree.
ERROR: Build failed for target 'images' in configuration 'windows-x86_64-server-slowdebug' (exit code 2)
=== Output from failing command(s) repeated here ===
* For target support_native_java.desktop_libfreetype_afblue.obj:
afblue.c
d:\java\forks\jdk\src\java.desktop\share\native\libfreetype\src\autofit\afblue.c(1): error C2220: the following warning is treated as an error
d:\java\forks\jdk\src\java.desktop\share\native\libfreetype\src\autofit\afblue.c(1): warning C4819: The file contains a character that cannot be represented in the current code page (932). Save the file in Unicode format to prevent data loss
d:\java\forks\jdk\src\java.desktop\share\native\libfreetype\src\autofit\afscript.h(1): warning C4819: The file contains a character that cannot be represented in the current code page (932). Save the file in Unicode format to prevent data loss
d:\java\forks\jdk\src\java.desktop\share\native\libfreetype\src\autofit\afblue.c(257): warning C4819: The file contains a character that cannot be represented in the current code page (932). Save the file in Unicode format to prevent data loss
... (rest of output omitted)
* For target support_native_java.desktop_libfreetype_afcjk.obj:
afcjk.c
...
Let us try using JITWatch on the sample Factorization program I have been using to learn about systems performance. Use these instructions from that blog post to get JITWatch:
git clone https://github.com/AdoptOpenJDK/jitwatch.git
cd jitwatch
mvn clean package
# Produces an executable jar in ui/target/jitwatch-ui-shaded.jar
java -jar ui/target/jitwatch-ui-shaded.jar
Start the factorization sample application such that a hotspot log file is generated. To do so, use the flags listed in the JITWatch Instructions · AdoptOpenJDK/jitwatch Wiki (github.com). I decide to redirect the output to a file to avoid filling the script with the additional logging output.
Click on the “Open Log” button in JITWatch then select the hotspot*.log file. Next, click on the Start button to process the JIT log.
Opening a HotSpot Log FileProcessed HotSpot LogViewing JIT-compiled Class Members
Clicking on a class member opens another window with the corresponding assembly instructions generated by the JIT. I haven’t set up any source code locations but the assembly instructions are still displayed.
Setting up MVN on Windows
To run JITWatch on Windows, download the Maven binaries from Maven – Download Apache Maven and verify the hashes using certutil. Extract the downloaded .zip file using tar. Here are the instructions I used in Git Bash.
mkdir -p /c/java/binaries/apache
cd /c/java/binaries/apache
curl -Lo apache-maven-3.9.3-bin.zip https://dlcdn.apache.org/maven/maven-3/3.9.3/binaries/apache-maven-3.9.3-bin.zip
certutil -hashfile apache-maven-3.9.3-bin.zip SHA512
# shasum -a 512 apache-maven-3.9.3-bin.zip
tar xf apache-maven-3.9.3-bin.zip
To store encrypted git credentials on disk in Ubuntu, install pass and the git-credential-manager. We will use gpg to generate a key that pass will use for secure storage and retrieval of credentials. Use these commands to get everything set up for git:
saint@ubuntuvm:~/repos/scratchpad$ git push
Username for 'https://github.com': swesonga
Password for 'https://swesonga@github.com':
remote: Permission to swesonga/scratchpad.git denied to swesonga.
fatal: unable to access 'https://github.com/swesonga/scratchpad/': The requested URL returned error: 403
saint@ubuntuvm:~/repos/scratchpad$ sudo dpkg -i ~/Downloads/gcm-linux_amd64.2.1.2.deb
[sudo] password for saint:
Selecting previously unselected package gcm.
(Reading database ... 272980 files and directories currently installed.)
Preparing to unpack .../gcm-linux_amd64.2.1.2.deb ...
Unpacking gcm (2.1.2) ...
Setting up gcm (2.1.2) ...
saint@ubuntuvm:~/repos/scratchpad$ which git-credential-manager
/usr/local/bin/git-credential-manager
saint@ubuntuvm:~/repos/scratchpad$ git-credential-manager configure
Configuring component 'Git Credential Manager'...
Configuring component 'Azure Repos provider'...
The git push experience is now different:
saint@ubuntuvm:~/repos/scratchpad$ git push
fatal: No credential store has been selected.
Set the GCM_CREDENTIAL_STORE environment variable or the credential.credentialStore Git configuration setting to one of the following options:
secretservice : freedesktop.org Secret Service (requires graphical interface)
gpg : GNU `pass` compatible credential storage (requires GPG and `pass`)
cache : Git's in-memory credential cache
plaintext : store credentials in plain-text files (UNSECURE)
See https://aka.ms/gcm/credstores for more information.
Username for 'https://github.com':
saint@ubuntuvm:~/repos/scratchpad$ git config --global credential.credentialStore
saint@ubuntuvm:~/repos/scratchpad$ git push
fatal: Password store has not been initialized at '/home/saint/.password-store'; run `pass init <gpg-id>` to initialize the store.
See https://aka.ms/gcm/credstores for more information.
Username for 'https://github.com':
Since I own the VM, I don’t mind credentials being stored on disk (but not in plain text), so I set up gpg and pass as instructed.
saint@ubuntuvm:~$ gpg --gen-key
gpg (GnuPG) 2.2.27; Copyright (C) 2021 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Note: Use "gpg --full-generate-key" for a full featured key generation dialog.
GnuPG needs to construct a user ID to identify your key.
Real name: Saint Wesonga
Email address: saint@swesonga.org
You selected this USER-ID:
"Saint Wesonga <saint@swesonga.org>"
...
saint@ubuntuvm:~$ sudo apt install pass
[sudo] password for saint:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
libqrencode4 qrencode tree xclip
Suggested packages:
libxml-simple-perl python ruby
The following NEW packages will be installed:
libqrencode4 pass qrencode tree xclip
0 upgraded, 5 newly installed, 0 to remove and 92 not upgraded.
Need to get 151 kB of archives.
After this operation, 442 kB of additional disk space will be used.
Do you want to continue? [Y/n]
...
saint@ubuntuvm:~$ pass init ABCDEF0123456789
mkdir: created directory '/home/saint/.password-store/'
Password store initialized for ABCDEF0123456789
Apparently I used the wrong value for the key but git push is unfazed – it pushes successfully after the browser authentication completes. I’m not sure what is happening now since browser authentication is in use but as long as I can push, I can forge ahead with other tasks.
saint@ubuntuvm:~/repos/scratchpad$ git push
info: please complete authentication in your browser...
fatal: Failed to encrypt file '/home/saint/.password-store/git/https/github.com/swesonga.gpg' with gpg. exit=2, out=, err=gpg: <WRONG HEX VALUE>: skipped: No public key
gpg: [stdin]: encryption failed: No public key
Enumerating objects: 11, done.
Counting objects: 100% (11/11), done.
Delta compression using up to 6 threads
Compressing objects: 100% (5/5), done.
Writing objects: 100% (6/6), 745 bytes | 745.00 KiB/s, done.
Total 6 (delta 3), reused 0 (delta 0), pack-reused 0
remote: Resolving deltas: 100% (3/3), completed with 3 local objects
Update: 2023-09-20. Use pass rm -r git to authenticate in the browser the next time git push is executed (e.g. if the password store secret is lost).
When Experimenting with perf on Linux, I used an Ubuntu VM. This can be a bit more cumbersome when simply trying to understand what various Linux commands can do. I decided to try using WSL to experiment with perf. Running wsl from the command line was sufficient to determine how to install the Ubuntu distribution.
C:\dev> wsl
Windows Subsystem for Linux has no installed distributions.
Distributions can be installed by visiting the Microsoft Store:
https://aka.ms/wslstore
C:\dev> wsl --install
Windows Subsystem for Linux is already installed.
The following is a list of valid distributions that can be installed.
Install using 'wsl --install -d <Distro>'.
NAME FRIENDLY NAME
Ubuntu Ubuntu
Debian Debian GNU/Linux
kali-linux Kali Linux Rolling
Ubuntu-18.04 Ubuntu 18.04 LTS
Ubuntu-20.04 Ubuntu 20.04 LTS
Ubuntu-22.04 Ubuntu 22.04 LTS
OracleLinux_7_9 Oracle Linux 7.9
OracleLinux_8_7 Oracle Linux 8.7
OracleLinux_9_1 Oracle Linux 9.1
SUSE-Linux-Enterprise-Server-15-SP4 SUSE Linux Enterprise Server 15 SP4
openSUSE-Leap-15.4 openSUSE Leap 15.4
openSUSE-Tumbleweed openSUSE Tumbleweed
C:\dev> wsl --install -d Ubuntu-22.04
Installing: Ubuntu 22.04 LTS
Ubuntu 22.04 LTS has been installed.
Launching Ubuntu 22.04 LTS...
Creating a UNIX user account
Installing perf
Install the linux-tools-generic package then check the perf version as follows:
Once the WSL Ubuntu distro installation completed and I have created a user account, I start by checking the perf --version lets you know how it can be installed:
saint@machine:~$ perf --version
Command 'perf' not found, but can be installed with:
sudo apt install linux-intel-iotg-tools-common # version 5.15.0-1027.32, or
sudo apt install linux-nvidia-tools-common # version 5.15.0-1023.23
sudo apt install linux-tools-common # version 5.15.0-71.78
sudo apt install linux-nvidia-5.19-tools-common # version 5.19.0-1009.9
sudo apt install linux-nvidia-tegra-tools-common # version 5.15.0-1012.12
Since I’m not looking for anything vendor specific, I try to install the linux-tools-common package.
saint@machine:~$ sudo apt install linux-tools-common
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
linux-tools-common
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 290 kB of archives.
After this operation, 823 kB of additional disk space will be used.
Ign:1 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 linux-tools-common all 5.15.0-71.78
Err:1 http://security.ubuntu.com/ubuntu jammy-updates/main amd64 linux-tools-common all 5.15.0-71.78
404 Not Found [IP: ... 80]
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/l/linux/linux-tools-common_5.15.0-71.78_all.deb 404 Not Found [IP: ... 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
saint@machine:~$ sudo apt install linux-tools-common
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
linux-tools-common
0 upgraded, 1 newly installed, 0 to remove and 41 not upgraded.
Need to get 277 kB of archives.
After this operation, 833 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 linux-tools-common all 5.15.0-73.80 [277 kB]
Fetched 277 kB in 0s (793 kB/s)
Selecting previously unselected package linux-tools-common.
(Reading database ... 24137 files and directories currently installed.)
Preparing to unpack .../linux-tools-common_5.15.0-73.80_all.deb ...
Unpacking linux-tools-common (5.15.0-73.80) ...
Setting up linux-tools-common (5.15.0-73.80) ...
Processing triggers for man-db (2.10.2-1) ...
Can we run a perf command now? No, perf not found for my kernel.
saint@machine:~$ perf --version
WARNING: perf not found for kernel 5.10.102.1-microsoft
You may need to install the following packages for this specific kernel:
linux-tools-5.10.102.1-microsoft-standard-WSL2
linux-cloud-tools-5.10.102.1-microsoft-standard-WSL2
You may also want to install one of the following packages to keep up to date:
linux-tools-standard-WSL2
linux-cloud-tools-standard-WSL2
Is that really my kernel version? Yes it is.
saint@mymachine:~$ uname -a
Linux mymachine 5.10.102.1-microsoft-standard-WSL2 #1 SMP Wed Mar 2 00:30:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Unfortunately, the suggested packages cannot be found:
saint@machine:~$ sudo apt install linux-tools-standard-WSL2
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package linux-tools-standard-WSL2
saint@machine:~$ sudo apt install linux-tools-5.10.102.1-microsoft-standard-WSL2
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package linux-tools-5.10.102.1-microsoft-standard-WSL2
E: Couldn't find any package by glob 'linux-tools-5.10.102.1-microsoft-standard-WSL2'
nt@machine:~$ sudo apt-get install linux-tools-5.10.102.1-microsoft-standard-WSL2
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package linux-tools-5.10.102.1-microsoft-standard-WSL2
E: Couldn't find any package by glob 'linux-tools-5.10.102.1-microsoft-standard-WSL2'
E: Couldn't find any package by regex 'linux-tools-5.10.102.1-microsoft-standard-WSL2'
The interesting thing about this is that the version numbers shown in the list of packages to be installed do not match my kernel version. However, the installation succeeds.
saint@machine:~$ sudo apt install linux-tools-generic
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
linux-tools-5.15.0-73 linux-tools-5.15.0-73-generic
The following NEW packages will be installed:
linux-tools-5.15.0-73 linux-tools-5.15.0-73-generic linux-tools-generic
0 upgraded, 3 newly installed, 0 to remove and 41 not upgraded.
Need to get 7931 kB of archives.
After this operation, 27.3 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 linux-tools-5.15.0-73 amd64 5.15.0-73.80 [7926 kB]
Get:2 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 linux-tools-5.15.0-73-generic amd64 5.15.0-73.80 [1786 B]
Get:3 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 linux-tools-generic amd64 5.15.0.73.71 [2308 B]
Fetched 7931 kB in 2s (5163 kB/s)
Selecting previously unselected package linux-tools-5.15.0-73.
(Reading database ... 24210 files and directories currently installed.)
Preparing to unpack .../linux-tools-5.15.0-73_5.15.0-73.80_amd64.deb ...
Unpacking linux-tools-5.15.0-73 (5.15.0-73.80) ...
Selecting previously unselected package linux-tools-5.15.0-73-generic.
Preparing to unpack .../linux-tools-5.15.0-73-generic_5.15.0-73.80_amd64.deb ...
Unpacking linux-tools-5.15.0-73-generic (5.15.0-73.80) ...
Selecting previously unselected package linux-tools-generic.
Preparing to unpack .../linux-tools-generic_5.15.0.73.71_amd64.deb ...
Unpacking linux-tools-generic (5.15.0.73.71) ...
Setting up linux-tools-5.15.0-73 (5.15.0-73.80) ...
Setting up linux-tools-5.15.0-73-generic (5.15.0-73.80) ...
Setting up linux-tools-generic (5.15.0.73.71) ...
perf --version still fails though. It’s not a symlink to anything else.
saint@machine:~$ ls -l `which perf`
-rwxr-xr-x 1 root root 1622 May 15 07:10 /usr/bin/perf
However, there is a user that was able to use perf by running the tool in the /usr/lib/linux-tools/… directory. Sure enough, this does the trick!
saint@machine:~$ /usr/lib/linux-tools/5.15.0-73-generic/perf --version
perf version 5.15.98
Sharing Files Between Windows and WSL Ubuntu
I was curious about whether I could generate a report from a perf.data file generated on another machine. The docs on Working across file systems show how easy it is to use a file on the Windows file system:
cd /mnt/c/dev/reports
/usr/lib/linux-tools/5.15.0-73-generic/perf report -n --stdio > report.txt
This doesn’t work though. The command fails after about 40 seconds with the error No kallsyms or vmlinux with build-id 5c3d8... was found.
mkdir -p ~/java/binaries/jdk/x64
cd ~/java/binaries/jdk/x64
wget https://aka.ms/download-jdk/microsoft-jdk-17.0.7-linux-x64.tar.gz
tar xzf microsoft-jdk-17.0.7-linux-x64.tar.gz
Test the factorization application to verify that the Java build works.
export JAVA_HOME=~/java/binaries/jdk/x64/jdk-17.0.7+7
cd ~/repos/scratchpad/demos/java/FindPrimes
$JAVA_HOME/bin/javac Factorize.java
$JAVA_HOME/bin/java Factorize 123890571352112309857
# Use 4 threads to speed things up
$JAVA_HOME/bin/java Factorize 123890571352112309857 CUSTOM_THREAD_COUNT_VIA_THREAD_CLASS 4
We will need the PrintAssembly option to disassemble the code generated by the compiler when running a Java program. This option requires diagnostic VM options to be unlocked. This is the full command line for generating the disassembly from the application’s execution. The output is redirected to a code.asm file since it can be voluminous.
In the above example, I have used a Java build in a custom path. If you are using a Java build that is already installed, then a few extra steps might be needed to determine where the JAVA_HOME path, e.g.
saint@ubuntuvm:~$ which java
/usr/bin/java
saint@ubuntuvm:~$ ls -l `which java`
saint@ubuntuvm:~$ ls -l /etc/alternatives/java
In the post on Experimenting with Async Profiler, I mentioned the basic (trial division) integer factorization app I wrote. I’ve been experimenting with perf to see what the system looks like when running this application. On Ubuntu, I started with this command:
perf record -F 97 -a -g -- sleep 10
Turns out perf isn’t installed by default.
WARNING: perf not found for kernel 5.19.0-41
You may need to install the following packages for this specific kernel:
linux-tools-5.19.0-41-generic
linux-cloud-tools-5.19.0-41-generic
You may also want to install one of the following packages to keep up to date:
linux-tools-generic
linux-cloud-tools-generic
Interestingly, running sudo apt install linux-tools-generic only picks up 5.17:
...
The following NEW packages will be installed:
linux-tools-5.15.0-72 linux-tools-5.15.0-72-generic linux-tools-generic
...
which perf now shows /usr/bin/perf but even perf -v fails with the above warning so I have to run
sudo apt install linux-tools-5.19.0-41-generic
...
The following NEW packages will be installed:
linux-hwe-5.19-tools-5.19.0-41 linux-tools-5.19.0-41-generic
...
Once that completes, perf can now run but perf version doesn’t display anything meaningful. Back to the original command:
perf record -F 97 -a -g -- sleep 10
This fails with an error about restricted access. Interesting reading but I just use sudo and carry on.
Error:
Access to performance monitoring and observability operations is limited.
Consider adjusting /proc/sys/kernel/perf_event_paranoid setting to open
access to performance monitoring and observability operations for processes
without CAP_PERFMON, CAP_SYS_PTRACE or CAP_SYS_ADMIN Linux capability.
More information can be found at 'Perf events and tool security' document:
https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html
perf_event_paranoid setting is 4:
-1: Allow use of (almost) all events by all users
Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK
>= 0: Disallow raw and ftrace function tracepoint access
>= 1: Disallow CPU event access
>= 2: Disallow kernel profiling
To make the adjusted perf_event_paranoid setting permanent preserve it
in /etc/sysctl.conf (e.g. kernel.perf_event_paranoid = <setting>)
Once the command completes, a perf.data file is created in the current directory. To generate a report, run this command. See the sample perf-report.txt file on GitHub.
perf report -n --stdio > perf-report.txt
To generate a flame graph, use Brendan Gregg’s scripts:
cd ~/repos
git clone https://github.com/brendangregg/FlameGraph
cd -
perf script --header > stacks.txt
~/repos/FlameGraph/stackcollapse-perf.pl < stacks.txt | ~/repos/FlameGraph/flamegraph.pl --hash > myflamegraph.svg
I have been studying the performance of a simple Java application (for integer factorization) using async-profiler. The application’s source code is on GitHub.
async-profiler is a low overhead sampling profiler for Java that does not suffer from Safepoint bias problem.
Once the application is running, use the profiler.sh script to attach to the Java process and start profiling it. I was interested in wall clock profiling. This is specified using the -e wall argument (see Part 2: Improving Performance with Async-profiler by Andrei Pangin. – YouTube). The command line below will profile the Java application with a 5ms sampling interval for a duration (-d) of 10 seconds.
# macos:
cd ~/java/binaries/async-profiler-2.9-macos
# Linux:
cd ~/java/binaries/async-profiler-2.9-linux
./profiler.sh -e wall -t -i 5ms -d 10 -f result.html jps
The jps argument above lets the profiler.sh script determine which Java process is running by calling The jps Command (oracle.com). If there are multiple Java processes, then run jps first to determine the process id of the one to be profiled then explicitly pass that pid to profiler.sh e.g.
To find out file types on macos, run file -I rawdata. In my case, I had flamegraph data that was shared as application/gzip (causing unzip to fail with End-of-central-directory signature not found. I needed to use gzip -d rawdata.
