| commit | 103eb0f9bc4a237c84eba0d7c90e79357b5d880a | [log] [tgz] |
|---|---|---|
| author | Bob Badour <bbadour@google.com> | Mon Jan 10 13:50:57 2022 -0800 |
| committer | Bob Badour <bbadour@google.com> | Tue Jan 11 10:40:50 2022 -0800 |
| tree | 9d3d337bf8d54ed4e7a2ad6898d1ba14fd53f3e8 | |
| parent | 5446a6f8e172322b5e38126974717fc634c0fee8 [diff] |
Performance and scale.
Defer edge creation.
Don't create edges until the count is known to avoid repeated allocate+
copy operatios.
Limit resolutions.
Allow only a single resolution condition set per target, and overwrite
intermediate results. Reduces memory and obviates allocations.
Propagate fewer conditions.
Instead of propagating notice conditions to parents in graph during
initial resolve, leave them on leaf node, and attach to ancestors in
the final walk. Reduces copies.
Parallelize resolutions.
Use goroutines, mutexes, and waitgroups to resolve branches of the
graph in parallel. Makes better use of available cores.
Don't accumulate resolutions inside non-containers.
During the final resolution walk, only attach actions to ancestors from
the root down until the 1st non-aggregate. Prevents an explosion of
copies in the lower levels of the graph.
Drop origin for scale.
Tracking the origin of every potential origin for every restricted
condition does not scale. By dropping origin, propagating from top
to bottom can prune many redundant paths avoiding an exponential
explosion.
Conditions as bitmask.
Use bit masks for license conditions and condition sets. Reduces maps
and allocations.
Bug: 68860345
Bug: 151177513
Bug: 151953481
Test: m all
Test: m systemlicense
Test: m listshare; out/soong/host/linux-x86/bin/listshare ...
Test: m checkshare; out/soong/host/linux-x86/bin/checkshare ...
Test: m dumpgraph; out/soong/host/linux-x86/dumpgraph ...
Test: m dumpresolutions; out/soong/host/linux-x86/dumpresolutions ...
where ... is the path to the .meta_lic file for the system image. In my
case if
$ export PRODUCT=$(realpath $ANDROID_PRODUCT_OUT --relative-to=$PWD)
... can be expressed as:
${PRODUCT}/gen/META/lic_intermediates/${PRODUCT}/system.img.meta_lic
Change-Id: Ia2ec1b818de6122c239fbd0824754f1d65daffd3
This is the Makefile-based portion of the Android Build System.
For documentation on how to run a build, see Usage.txt
For a list of behavioral changes useful for Android.mk writers see Changes.md
For an outdated reference on Android.mk files, see build-system.html. Our Android.mk files look similar, but are entirely different from the Android.mk files used by the NDK build system. When searching for documentation elsewhere, ensure that it is for the platform build system -- most are not.
This Makefile-based system is in the process of being replaced with Soong, a new build system written in Go. During the transition, all of these makefiles are read by Kati, and generate a ninja file instead of being executed directly. That's combined with a ninja file read by Soong so that the build graph of the two systems can be combined and run as one.