Reduce startup time for gambit --help and gambit --version#590
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anderkve wants to merge 3 commits into
Open
Reduce startup time for gambit --help and gambit --version#590anderkve wants to merge 3 commits into
gambit --help and gambit --version#590anderkve wants to merge 3 commits into
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…nary loads. By letting the gambit_preload library identify trivial gambit invocations like "gambit --help" and "gambit --version" and produce the correct CLI help text, we avoid having to wait for the full GAMBIT initialisation for these simple cases. (The GAMBIT initialisation typically takes a few seconds.)
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This PR uses two shortcuts to reduce the GAMBIT startup time for the trivial GAMBIT invocations
gambit --help,gambit --versionand simplygambitwith no arguments. In all these cases we just want to print some message to the terminal and exit, so there is no need to wait for the full GAMBIT initialisation.The first shortcut is in
core.cpp, where we get in before thecheck_databasesstep. On testing this saved ~1 second (~25% of the GAMBIT init time on those tests).The second shortcut lives in the preload library and is for now Linux-only (it uses
/proc/self/cmdline). Here the preload library directly identifies the trivial gambit invocations and outputs the correct terminal output (version number or CLI help text) and exits directly, without ever initialising the main gambit executable. So with this shortcut there is ~no startup time at all. For non-Linux systems, we just continue to the main GAMBIT executable where the first shortcut still saves us a bit of time.To avoid duplicating the CLI help text in the code, it has been extracted to a header file
gambit/Core/cli_help_text.hpp.