On Wed, 4 Dec 2024 at 05:20, davidr via groups.io <davidr=ghs....@groups.io> wrote: > > Hi, > > I was testing out dumping a raw OVMF_VARS.fd into an FDF data section and > noticed that my rebuilds of OVMF with no code changes went from 15 seconds to > over 1 minute. The only change was the data in the NV_VARIABLE_STORE data > section in OvmfPkg/Include/Fdf/VarStore.fdf.inc which changed the size of the > file from about 4 KiB to about 256 KiB. I was rather curious as to why my > build times changed so much and profiled the build process with cProfile. > Specifically > https://github.com/tianocore/edk2/blob/master/BaseTools/Source/Python/GenFds/FdfParser.py#L279 > takes the vast majority of the time. > > You can reproduce this by adding 256 KiB of "#" characters to the end of > OvmfPkg/Include/Fdf/VarStore.fdf.inc and building OVMF, which produced this > result for me: > Build total time: 00:01:31 > 34883442 function calls (34368868 primitive calls) in 91.191 seconds > Ordered by: internal time > ncalls tottime percall cumtime percall filename:lineno(function) > 18769 73.501 0.004 75.942 0.004 > FdfParser.py:276(_SkipWhiteSpace) > 728 5.738 0.008 5.738 0.008 {method 'acquire' of > '_thread.lock' objects} > 12 1.569 0.131 1.569 0.131 {method 'poll' of 'select.poll' > objects} > 2849255 1.248 0.000 1.439 0.000 FdfParser.py:354(_GetOneChar) > 2305959 0.873 0.000 1.131 0.000 FdfParser.py:293(_EndOfFile) > 5374641 0.831 0.000 0.831 0.000 FdfParser.py:368(_CurrentChar) > 2 0.526 0.263 1.278 0.639 FdfParser.py:497(PreprocessFile) > > Changing _SkippedChars from a string to StringIO reduced my build time to 19 > seconds: > Build total time: 00:00:19 > 36552029 function calls (36037563 primitive calls) in 18.618 seconds > Ordered by: internal time > ncalls tottime percall cumtime percall filename:lineno(function) > 728 5.391 0.007 5.391 0.007 {method 'acquire' of > '_thread.lock' objects} > 18769 1.593 0.000 3.452 0.000 > FdfParser.py:277(_SkipWhiteSpace) > 12 1.551 0.129 1.551 0.129 {method 'poll' of 'select.poll' > objects} > 2849255 0.850 0.000 0.979 0.000 FdfParser.py:355(_GetOneChar) > 5374641 0.742 0.000 0.742 0.000 FdfParser.py:369(_CurrentChar) > 2305959 0.741 0.000 0.951 0.000 FdfParser.py:294(_EndOfFile) > 2 0.511 0.256 1.237 0.618 FdfParser.py:498(PreprocessFile) > > All of these tests were run using the python3 binary provided in the docker > container created by > https://github.com/tianocore/containers/tree/main/Ubuntu-22/Dockerfile. > > This seems like an easy change to make builds a tiny bit faster. >
Thanks for the report. Mind sending a patch / PR ? -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#120866): https://edk2.groups.io/g/devel/message/120866 Mute This Topic: https://groups.io/mt/109914552/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
