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https://github.com/scottlamb/moonfire-nvr.git
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0aadf227c1
I'm seeing what is possible performance-wise in the current C++ before
trying out Go and Rust implementations.
* use the google benchmark framework and some real data.
* use release builds - I hadn't done this in a while, and there were a
few compile errors that manifested only in release mode. Update the
readme to suggest using a release build.
* optimize the varint decoder and SampleIndexIterator to branch less.
* enable link-time optimization for release builds.
* add some support for feedback-directed optimization. Ideally "make"
would automatically produce the "generate" build outputs with a
different object/library/executable suffix, run the generate
benchmark, and then produce the "use" builds. This is not that fancy;
you have to run an arcane command:
alias cmake='cmake -DCMAKE_BUILD_TYPE=Release'
cmake -DPROFILE_GENERATE=true -DPROFILE_USE=false .. && \
make recording-bench && \
src/recording-bench && \
cmake -DPROFILE_GENERATE=false -DPROFILE_USE=true .. && \
make recording-bench && \
perf stat -e cycles,instructions,branches,branch-misses \
src/recording-bench --benchmark_repetitions=5
That said, the results are dramatic - at least 50% improvement. (The
results weren't stable before as small tweaks to the code caused a
huge shift in performance, presumably something something branch
alignment something something.)
14 lines
254 B
Plaintext
14 lines
254 B
Plaintext
*.swp
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build
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debug
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release
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obj-*
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cameras.sql
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debian/files
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debian/moonfire-nvr.debhelper.log
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debian/moonfire-nvr.postinst.debhelper
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debian/moonfire-nvr.postrm.debhelper
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debian/moonfire-nvr.prerm.debhelper
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debian/moonfire-nvr.substvars
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debian/moonfire-nvr/
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