buildsystem: switch to dynamic scheduler #4092
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Drop Also, add a fix for a couple of simple add-ons that were breaking due to lack of 7za when being packaged before |
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Squashed the latest commits. |
… handles failed jobs
cp (and potentially mkdir -p) are not atomic, and we have seen situations where two packages concurrently copying the same file (eg. the udev rule for xf86-video-nvidia and xf86-video-nvidia-legacy) will succeed for one package but the other package fails with a "file exists" error (as the file didn't exist when it checked, but does exist when it actually copies the file). Not even cp -f will avoid this issue. There are several workarounds, but the most practical (and general) solution is to ensure sequential updates of the image and shared sysroot directories.
HiassofT
approved these changes
Jan 20, 2020
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Thanks to @dhewg for the initial work/prompting on this.
This PR moves us beyond the current "static plan" schedule which has it's limitations. Optimising the static plan can only take us so far, and due to the fairly "dumb" nature of
parallelwe're stuck with several limitations.Replacing
parallelwith something that is more knowledgeable about the LibreELEC build process and switching to a "dynamic" schedule optimises the remaining few minutes out of the static plan, while also allowing us to more efficiently implement in Python what we had previously had to support in shell code (ie. job failure handling) and eliminating recursive dependency stamp checking and subequent dependency building.With the dynamic scheduler it is no longer necessary to recursively
buildorinstallpackage dependencies - the exception beinginitramfs:target- which results in fewerunpacklocks and stamp checks. Having eliminated recursivebuildandinstallwe now only need to acquire locks duringunpackandreconf- all other "locks" are purely for logging purposes.By default logs will continue to be "grouped" or "burst" as they are now. The output from each log will be sent to
stdoutby default, although output tostdoutcan be disabled entirely (--log-combine never) or output only on failure (--log-combine fail), both of which may help reduce IO.Debugging can be enabled with
--debug(MTDEBUG=yes) with output written to${THREAD_CONTROL}/debug.log.Verbose output can be enabled with
--verbose(MTVERBOSE=yes) with output written tostderr.Completed job information can be written to
${THREAD_CONTROL}/joblogif--joblogis enabled (which it is, by default). The following space-delimited fields for each job will be written as each job is completed:DONE,FAIL)build,install)linux:target)--log-burstis enabled)Below are some before/after comparisons for Generic and RPi2 builds (
imageandalladdons)--burst --log-combine alwaysTHREADCOUNT=4/CONCURRENCY_MAKE_LEVEL=8(ie.T4C8), the second forT8C8to demonstrate the difference when "over committing" resources-lswitch forninjaandmake)Generic,
image(T4C8andT8C8):Generic,
alladdons (T4C8andT8C8):RPi2,
image(T4C8andT8C8):RPi2,
alladdons (T4C8andT8C8):