From 78f25d9a9c5b5f87d3dcf76d1356d1c906e82103 Mon Sep 17 00:00:00 2001 From: Julien Stephan Date: Wed, 6 Nov 2024 14:54:47 +0100 Subject: dev-manual: add bblock documentation bblock is a helper tool to lock/unlock tasks and recipes to specific signatures. Add a documentation page for it. (From yocto-docs rev: a082aa39840587d3af6c3f4a2c2747564ca37414) Signed-off-by: Julien Stephan Reviewed-by: Antonin Godard Signed-off-by: Antonin Godard Signed-off-by: Richard Purdie --- documentation/dev-manual/bblock.rst | 129 ++++++++++++++++++++++++++++++++++++ documentation/dev-manual/index.rst | 1 + 2 files changed, 130 insertions(+) create mode 100644 documentation/dev-manual/bblock.rst (limited to 'documentation/dev-manual') diff --git a/documentation/dev-manual/bblock.rst b/documentation/dev-manual/bblock.rst new file mode 100644 index 0000000000..68292903ba --- /dev/null +++ b/documentation/dev-manual/bblock.rst @@ -0,0 +1,129 @@ +.. SPDX-License-Identifier: CC-BY-SA-2.0-UK + +Locking and Unlocking Recipes Using ``bblock`` +********************************************** + +By design, the OpenEmbedded build system builds everything from scratch +unless BitBake determines that specific tasks do not require rebuilding. +At startup, it computes a signature for all tasks, based on the task's input. +Then, it compares these signatures with the ones from the sstate cache (if they +exist). Any changes cause the task to rerun. + +During development, changes might trigger BitBake to rebuild certain +recipes, even when we know they do not require rebuilding at that stage. +For example, modifying a recipe can lead to rebuilding its native +counterpart, which might prove unnecessary. Editing the ``python3`` recipe, +for instance, can prompt BitBake to rebuild ``python3-native`` along with any +recipes that depend on it. + +To prevent this, use ``bblock`` to lock specific tasks or recipes to +specific signatures, forcing BitBake to use the sstate cache for them. + +.. attention:: + + Use ``bblock`` only during the development phase. + + Forcing BitBake to use the sstate cache, regardless of input changes, means + the recipe metadata no longer directly reflect the output. Use this feature + with caution. If you do not understand why signatures change, see the section + on :yocto_wiki:`understanding what changed `. + + +Locking tasks and recipes +------------------------- + +To lock a recipe, use:: + + $ bblock recipe + +You can also use a space-separated list of recipes to lock multiple recipes:: + + $ bblock recipe1 recipe2 + +Locking a recipe means locking all tasks of the recipe. If you need to +lock only particular tasks, use the `-t` option with a comma-separated +list of tasks:: + + $ bblock -t task1,task2 recipe + + +Unlocking tasks and recipes +--------------------------- + +To unlock a recipe, use the ``-r`` option:: + + $ bblock -r recipe + +You can also use a space-separated list of recipes to unlock multiple recipes:: + + $ bblock -r recipe1 recipe2 + +Unlocking a recipe means unlocking all tasks of the recipe. If you need to +unlock only particular tasks use the ``-t`` option with a comma-separated +list of tasks:: + + $ bblock -r -t task1,task2 recipe + +To unlock all recipes, do not specify any recipe:: + + $ bblock -r + + +Configuration file +------------------ + +``bblock`` will dump the signatures in the ``build/conf/bblock.conf`` file, +included by default in :oe_git:`meta/conf/bitbake.conf `. + +To dump the file, use the ``-d`` option:: + + $ bblock -d + + +Locking mechanism +----------------- + +``bblock`` computes the signature(s) of the task(s) and sets the 3 following +variables: :term:`SIGGEN_LOCKEDSIGS`, :term:`SIGGEN_LOCKEDSIGS_TYPES` +and :term:`SIGGEN_LOCKEDSIGS_TASKSIG_CHECK`. + +In particular, ``bblock`` sets:: + + SIGGEN_LOCKEDSIGS_TASKSIG_CHECK = "info" + SIGGEN_LOCKEDSIGS_TYPES += "${PACKAGE_ARCHS}" + + SIGGEN_LOCKEDSIGS_ += "::" + +This produces architecture specific locks and reminds user that some tasks +have locked signatures. + +Example +------- + +When working on the ``python3`` recipe, we can lock ``python3-native`` with +the following:: + + $ bblock python3-native + $ bblock -d + # Generated by bblock + SIGGEN_LOCKEDSIGS_TASKSIG_CHECK = "info" + SIGGEN_LOCKEDSIGS_TYPES += "${PACKAGE_ARCHS}" + + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_patch:865859c27e603ba42025b7bb766c3cd4c0f477e4962cfd39128c0619d695fce7" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_populate_sysroot:f8fa5d3194cef638416000252b959e86d0a19f6b7898e1f56b643c588cdd8605" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_prepare_recipe_sysroot:fe295ac505d9d1143313424b201c6f3f2a0a90da40a13a905b86b874705f226a" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_fetch:1b6e4728fee631bc7a8a7006855c5b8182a8224579e32e3d0a2db77c26459f25" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_unpack:2ad74d6f865ef75c35c0e6bbe3f9a90923a6b2c62c18a3ddef514ea31fbc588f" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_deploy_source_date_epoch:15f89b8483c1ad7507480f337619bb98c26e231227785eb3543db163593e7b42" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_configure:7960c13d23270fdb12b3a7c426ce1da0d2f5c7cf5e5d3f5bdce5fa330eb7d482" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_compile:012e1d4a63f1a78fc2143bd90d704dbcf5865c5257d6272aa7540ec1cd3063d9" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_install:d3401cc2afa4c996beb154beaad3e45fa0272b9c56fb86e9db14ec3544c68f9d" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_build:fa88bb7afb9046c0417c24a3fa98a058653805a8b00eda2c2d7fea68fc42f882" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_collect_spdx_deps:cc9c53ba7c495567e9a38ec4801830c425c0d1f895aa2fc66930a2edd510d9b4" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_create_spdx:766a1d09368438b7b5a1a8e2a8f823b2b731db44b57e67d8b3196de91966f9c5" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_create_package_spdx:46f80faeab25575e9977ba3bf14c819489c3d489432ae5145255635108c21020" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_recipe_qa:cb960cdb074e7944e894958db58f3dc2a0436ecf87c247feb3e095e214fec0e4" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_populate_lic:15657441621ee83f15c2e650e7edbb036870b56f55e72e046c6142da3c5783fd" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_create_manifest:24f0abbec221d27bbb2909b6e846288b12cab419f1faf9f5006ed80423d37e28" + SIGGEN_LOCKEDSIGS_x86_64 += "python3-native:do_addto_recipe_sysroot:bcb6a1905f113128de3f88d702b706befd6a786267c045ee82532759a7c214d7" + diff --git a/documentation/dev-manual/index.rst b/documentation/dev-manual/index.rst index 9ccf60f701..7afd0d820e 100644 --- a/documentation/dev-manual/index.rst +++ b/documentation/dev-manual/index.rst @@ -48,5 +48,6 @@ Yocto Project Development Tasks Manual error-reporting-tool wayland qemu + bblock .. include:: /boilerplate.rst -- cgit v1.2.3-54-g00ecf