Skip to content

Latest commit

 

History

History
76 lines (49 loc) · 2.42 KB

CpuSampleLinuxSymbolResolveInterceptor.md

File metadata and controls

76 lines (49 loc) · 2.42 KB
Raw

The source code of this class is located at CpuSampleLinuxSymbolResolveInterceptor.hpp.

CpuSampleLinuxSymbolResolveInterceptor is an interceptor used to setup symbol names in model data.

It can resolve three types of symbol name:

  • Symbol name in ELF binary (normal, or dynamic)
  • Symbol name in linux kernel (load from /proc/kallsyms)
  • Custom symbol name (load from /map/perf-$pid.map)

Support for native programs

Native programs written in c, c++, go, etc are supported by default, usually you don't need to change any code to get it work. However, there some minor problems:

Some symbol names are missing

See this link: StackOverflow

For gcc and clang, use -rdynamic option may solve this problem.

The call chain is incomplete

See this link: StackOverflow

For gcc and clang, use -fomit-frame-pointer option may solve this problem.

Support for vm based programs

VM based programs written in java, .net, etc needs to do some extra works.

Java

For java you need a jvm agent from here.
Since upstream didn't support "agentpath" option I will use a fork here until this PR is merged.

Build perf-map-agent:

git clone https://github.com/trustin/perf-map-agent
cd perf-map-agent
export JAVA_HOME=/usr/lib/jvm/java-9-openjdk-amd64
cmake .
make
sudo cp -f out/libperfmap.so /usr/lib

Then execute your java program:

java -agentpath:/usr/lib/libperfmap.so programName

.Net

Support for .net(coreclr only) is very simple.
Just export the following environment variable and execute your .net program.

export COMPlus_PerfMapEnabled=1
dotnet programName.dll

It may cause many junk files leaved in "/tmp" if you don't clean it manually,
the suggested solution would be mount "/tmp" to a memory based temporary file system.

Example

Just call addInterceptor is enough.

Profiler<CpuSampleModel> profiler;
auto collector = profiler.useCollector<CpuSampleLinuxCollector>();
auto interceptor = profiler.addInterceptor<CpuSampleLinuxSymbolResolveInterceptor>();