load-time
Mesure the time it takes to load a shared library. Only useful for benchmarking, but that's already something!
Installation
Just:
> make
Creates the load-time binary. But really, it's just a simple source file of
a dozen of lines, so you should be able to compile it on your own on any Linux
box.
Then drop it where you want, add it to your PATH, not my business.
Usage
Basically:
> load-time /path/to/a/shared/library.so 142 us
For instance:
> load-time /usr/lib64/libm.so.6 142 us
Why
Some library takes more time to load than we would expect. There usually is a reason, this tool is the first stone I use to understand why. For instance, an investigation of the output of:
> valgrind --tool=callgrind load-time /usr/lib64/libstdc++.so.6 [...]
with kcachegrind tells me that std::ios_base::Init::Init() is the global
constructor that uses most of the libstdc++ startup time on my system.
load-time also tells me that it only takes a hundred of nanoseconds to load
the lib, which basically means it's probably fine :-)