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.
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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]
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Fetched 7931 kB in 2s (5163 kB/s)
Selecting previously unselected package linux-tools-5.15.0-73.
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Unpacking linux-tools-5.15.0-73 (5.15.0-73.80) ...
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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) ...
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Preparing to unpack .../linux-tools-generic_5.15.0.73.71_amd64.deb ...
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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.
We use SymChk to ensure that symbols are available for Windows applications. For the OpenJDK build, this command line can be used to ensure the symbols directory contains symbols for all the Java binaries:
/r causes SymChk to recursively search all subdirectories under the D:\java\binaries\jdk\x64\jdk-17.0.7+7\ directory for program files.
/s specifies the directories containing symbols and multiple directories should be separated with semicolons
Here’s the tail end of the SymChk output:
...
SYMCHK: api-ms-win-crt-utility-l1-1-0.dll FAILED - api-ms-win-crt-utility-l1-1-0.pdb mismatched or not found
SYMCHK: msvcp140.dll FAILED - msvcp140.amd64.pdb mismatched or not found
SYMCHK: ucrtbase.dll FAILED - ucrtbase.pdb mismatched or not found
SYMCHK: vcruntime140.dll FAILED - vcruntime140.amd64.pdb mismatched or not found
SYMCHK: vcruntime140_1.dll FAILED - vcruntime140_1.amd64.pdb mismatched or not found
SYMCHK: FAILED files = 46
SYMCHK: PASSED + IGNORED files = 440
The components that have failures are binaries that are external dependencies of the OpenJDK. Those failures can therefore be safely ignored. An interesting thing to note is that java.dll and java.exe are in the same folder in the OpenJDK installation. Since their symbol files are both called java.pdb, the symbols for java.exe are placed in a subdirectory called exe. This applies to other binaries with similar PDB filename conflicts. See the Symbol Path Syntax section for more details.
The YCSB_COMMAND passed to the Client class is set to -load and -t respectively, for the load and run arguments to the script. The -db argument specified which class to use for the database client. This comes from the second parameter to the script (grep is used to match the script’s 2nd argument with a line in bindings.properties that specifies the corresponding Java class).
Setting up YSCB with a MySQL Database
Database Installation
In addition to the original paper, Planet MySQL also has YCSB results for runs against a MySQL database. The ease of use of a local database prompts me to start out with MySQL as well. Ubuntu docs explain how to Install and configure a MySQL server.
saint@ubuntuvm2:~$ sudo apt install mysql-server
[sudo] password for saint:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
libaio1 libcgi-fast-perl libcgi-pm-perl libevent-core-2.1-7
libevent-pthreads-2.1-7 libfcgi-bin libfcgi-perl libfcgi0ldbl
libhtml-template-perl libmecab2 libprotobuf-lite23 mecab-ipadic
mecab-ipadic-utf8 mecab-utils mysql-client-8.0 mysql-client-core-8.0
mysql-common mysql-server-8.0 mysql-server-core-8.0
Suggested packages:
libipc-sharedcache-perl mailx tinyca
The following NEW packages will be installed:
libaio1 libcgi-fast-perl libcgi-pm-perl libevent-core-2.1-7
libevent-pthreads-2.1-7 libfcgi-bin libfcgi-perl libfcgi0ldbl
libhtml-template-perl libmecab2 libprotobuf-lite23 mecab-ipadic
mecab-ipadic-utf8 mecab-utils mysql-client-8.0 mysql-client-core-8.0
mysql-common mysql-server mysql-server-8.0 mysql-server-core-8.0
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Getting YCSB Sources
Now that MySQL is installed, we need the YCSB sources to run. I started out by cloning the YCSB repo.
mkdir -p ~/java/benchmarks/ycsb
cd ~/java/benchmarks/ycsb
git clone https://github.com/brianfrankcooper/YCSB
cd YCSB
As a Java repo rookie, I simply ran bin/ycsb.sh load basic -P workloads/workloada as mentioned in the readme without realizing that I needed to first build the repo, duh. That failed with this error:
$ export JAVA_HOME=~/java/binaries/jdk/x64/jdk-20+36
$ bin/ycsb.sh load basic -P workloads/workloada
Error: Could not find or load main class site.ycsb.db.JdbcDBCreateTable
Caused by: java.lang.ClassNotFoundException: site.ycsb.db.JdbcDBCreateTable
Use mvn to build the sources:
# Error: Could not find or load main class site.ycsb.db.JdbcDBCreateTable
# https://github.com/brianfrankcooper/YCSB/issues/257#issuecomment-104845560
sudo apt install maven
mvn clean package
I end up with test failures, what do you know?
Getting YCSB Binaries
I decided I might as well just follow the main readme steps and not deal with any build issues.
cd ~/java/benchmarks/ycsb
sudo apt install curl
curl -O --location https://github.com/brianfrankcooper/YCSB/releases/download/0.17.0/ycsb-0.17.0.tar.gz
tar xfvz ycsb-0.17.0.tar.gz
cd ycsb-0.17.0
Launching YCSB
Launch YCSB in the folder from the tar.gz file:
# Notice the version in the path below needs to be updated from what is used at
# https://github.com/brianfrankcooper/YCSB/tree/master/jdbc
#
# The MySQL connectors are at https://dev.mysql.com/downloads/connector/j/?os=26
java -cp jdbc-binding/lib/jdbc-binding-0.17.0.jar:../mysql-connector-j-8.0.32/mysql-connector-j-8.0.32.jar site.ycsb.db.JdbcDBCreateTable -P myjdbc.properties -n ycsbtable
Turns out the driver in the docs is outdated:
Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
Error in creating table. java.sql.SQLException: Access denied for user 'admin'@'localhost' (using password: YES)
CREATE DATABASE ycsb;
CREATE USER 'ycsbuser'@'localhost' IDENTIFIED BY 'ProfileIt!';
GRANT ALL PRIVILEGES ON * . * TO 'ycsbuser'@'localhost';
Hard to believe but the JdbcDBCreateTable class fails!
losing database connection.
Error in creating table. java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'PRIMARY KEY, FIELD0 TEXT, FIELD1 TEXT, FIELD2 TEXT, FIELD3 TEXT, FIELD4 TEXT, FI' at line 1
Loading workload...
Starting test.
Error in initializing the JDBS driver: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
site.ycsb.DBException: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at site.ycsb.db.JdbcDBClient.init(JdbcDBClient.java:228)
at site.ycsb.DBWrapper.init(DBWrapper.java:86)
at site.ycsb.ClientThread.run(ClientThread.java:91)
at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:375)
at site.ycsb.db.JdbcDBClient.init(JdbcDBClient.java:199)
... 3 more
bin/ycsb.sh run jdbc -P ../../mysqlworkload.properties
One question that arises is how to control the benchmark running time. There is a maxexecutiontime (in seconds) argument that can be passed to the benchmark.
bin/ycsb.sh run jdbc -P ../../mysqlworkload.properties -p maxexecutiontime=60
The run time is still about 12 seconds and an interesting message is displayed:
Loading workload...
Starting test.
Maximum execution time specified as: 60 secs
Adding shard node URL: jdbc:mysql://127.0.0.1:3306/ycsb
Using shards: 1, batchSize:-1, fetchSize: -1
DBWrapper: report latency for each error is false and specific error codes to track for latency are: []
Could not wait until max specified time, TerminatorThread interrupted.
[OVERALL], RunTime(ms), 6756
Looks like customizing the load is the way to prolong the benchmark:
# The number of records to load into the database initially.
recordcount=1000000
# The target number of operations to perform.
operationcount=10000
# Indicates how many inserts to do if less than recordcount.
# Useful for partitioning the load among multiple servers if the client is the bottleneck.
# Additionally workloads should support the "insertstart" property which tells them which record to start at.
insertcount=10000
