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| -rw-r--r-- | dependencies/analyses/README.md | 64 |
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diff --git a/dependencies/analyses/README.md b/dependencies/analyses/README.md new file mode 100644 index 000000000..70de3f621 --- /dev/null +++ b/dependencies/analyses/README.md @@ -0,0 +1,64 @@ +# A set of scripts and instructions that help to analyze and debloat go-lang dependencies. + +## Size of packages + +To analyze the size of all go packages used during the build process, pass the `-work -a` build flags to `go build`. +The `-a` flag forces go to rebuild all packages even if they are already up-to-date (e.g., in the build cache), while the `-work` flag instructs go to print path of the temporary work directory used for compiling the packages. +The path to the temporary work directory of `go-build` must be passed to `go-archive-analysis.sh` by setting it as an environment variable. +The analysis script will then read and parse the build data and print a sorted table of the package size in bytes followed by the package name. + +Running such an analysis on libpod may look as follows: + +``` +# 1) Build the podman binary with `-work -a`. + +[libpod]$ BUILDFLAGS="-work -a" make podman +[...] +WORK=/tmp/go-build794287815 + +# 2) Set the work directory as an environment variable and call the analysis script +[libpod]$ WORK=/tmp/go-build794287815 ./dependencies/analyses/go-archive-analysis.sh | head -n10 +17M github.com/containers/libpod/cmd/podman/cliconfig +13M github.com/containers/libpod/vendor/github.com/DataDog/zstd +10M github.com/containers/libpod/vendor/k8s.io/api/core/v1 +3.7M net/http +3.7M github.com/containers/libpod/libpod +3.2M runtime +2.7M github.com/containers/libpod/vendor/github.com/gogo/protobuf/proto +2.5M github.com/containers/libpod/vendor/k8s.io/apimachinery/pkg/apis/meta/v1 +2.3M github.com/containers/libpod/vendor/github.com/vishvananda/netlink +2.1M github.com/containers/libpod/cmd/podman/varlink +``` + +The output of the `go-archive-analysis.sh` script is a sorted table with the size in bytes followed by the package. +The size denotes the size of the compiled package (i.e., the `.a` file). + + +## Size of symbols in binary + +Once the binary is compiled, we can run another set of analyses on it. +The `nm-symbols-analysis.sh` is a wrapper around `go tool nm` and prints a table with size in bytes followed by the symbols name. +To avoid information overload, the scripts prints only symbols from the text/code segment. + +Running such an analysis on libpod may look as follows: + +``` +# 1) Compile the binary +[libpod]$ make podman +[...] + +# 2) Run the script with the binary as an argument +[libpod]$ ./dependencies/nm-symbols-analysis.sh ./bin/podman | grep "containers/libpod/libpod" | head -n10 +299 github.com/containers/libpod/libpod.(*BoltState).AddContainer +658 github.com/containers/libpod/libpod.(*BoltState).AddContainerToPod +2120 github.com/containers/libpod/libpod.(*BoltState).AddPod +3773 github.com/containers/libpod/libpod.(*BoltState).AddPod.func1 +965 github.com/containers/libpod/libpod.(*BoltState).AddVolume +1651 github.com/containers/libpod/libpod.(*BoltState).AddVolume.func1 +558 github.com/containers/libpod/libpod.(*BoltState).AllContainers +282 github.com/containers/libpod/libpod.(*BoltState).AllContainers.func1 +1121 github.com/containers/libpod/libpod.(*BoltState).AllContainers.func1.1 +558 github.com/containers/libpod/libpod.(*BoltState).AllPods +``` + +Running the script can help identify sources of bloat and reveal potential candidates (e.g., entire packages, types, or function) for refactoring. |