configure once, compile many times

Posted Apr 30, 2025 9:54 UTC (Wed) by NYKevin (subscriber, #129325)
In reply to: configure once, compile many times by marcH
Parent article: Barnes: Parallel ./configure

It doesn't help that configure is traditionally a shell script. The POSIX-compatible subset of the shell has no lighter-weight parallelism facility than spawning an entire process, with all of the usual problems that implies. Probably nobody thought it was worth it, before 24-core systems became a thing that normal people had on their desks.

configure once, compile many times

Posted Apr 30, 2025 10:26 UTC (Wed) by jengelh (guest, #33263) [Link] (2 responses)

When you have 24 threads, just run 24 configures (for different build types, different packages), problem solved ;-)

Also, with many platforms and (non-)standards having fallen out of fashion in the last two decades, a lot of tests are also more or less obsolete in the sense that one's configure.ac need not invoke them any more, like

$CC not supporting -o
ANSI C prototype support
Support for keywords "inline", "volatile", "const"
AC_SYS_LARGEFILE (just unconditionally -D_LARGEFILE_SOURCE?)

configure once, compile many times

Posted Apr 30, 2025 14:03 UTC (Wed) by abatters (✭ supporter ✭, #6932) [Link]

> When you have 24 threads, just run 24 configures (for different build types, different packages), problem solved ;-)

Indeed; that is what Yocto does.

configure once, compile many times

Posted Apr 30, 2025 14:49 UTC (Wed) by marcH (subscriber, #57642) [Link]

> When you have 24 threads, just run 24 configures (for different build types, different packages), problem solved ;-)

This is useful but it's a different type of inefficiency because all these threads repeat mostly the same things.

Some smart caching would help in both situations.