Meta mode

Meta mode is an incremental build option for FreeBSD, which uses bmake's meta mode and filemon(4) to create meta files. It substantially decreases the time it takes to build FreeBSD, by only building what has changed since the last build.

• src.conf(5)
• build(7)

Note: Enabling META_MODE also implies (enables) NO_CLEAN in the buildworld process

• /etc/src-env.conf:

WITH_META_MODE=YES

• kldload filemon
• You also need to make cleanworld once. If objects don't have .meta files then META_MODE won't do the right thing on an incremental build. (Source: [CFT WITH_META_MODE: Working incremental build)

Follow the FreeBSD Handbook: makeworld instructions.

• Don't mix WITH_META_MODE with ccache(1) as mentioned in this thread .
  • For all versions from 12.0-RELEASE and going forward, both technologies work as expected.
• WITH_META_MODE is not the same thing as WITH_DIRDEPS_BUILD, which is an alternative, experimental build system.
  • Building FreeBSD in meta mode
  • Improving the FreeBSD Build (BSDCan 2016)
  • Description of meta mode in bmake(1)
  • Speeding up builds on FreeBSD

• [CFT WITH_META_MODE: Working incremental build