plugin needed to handle lto object

[wanghenshui]

centos 神奇报错。

把AR改成gcc-ar传给编译器即可

另外centos还有使用旧的string ABI问题。这个问题没啥好办法，尽量静态编译全部编译，涉及交叉环境，准备多个编译库动态选择

[wanghenshui]

比如blade用Scons，把AR传给Scons就行

[wanghenshui]

http://hubicka.blogspot.com/2014/09/linktime-optimization-in-gcc-part-3.html

[wanghenshui]

https://www.reddit.com/r/Gentoo/comments/6b1dlc/plugin_needed_to_handle_lto_object_and_correct/

[wanghenshui]

https://chengzhaoxi.xyz/categories/AI%E6%A8%A1%E5%9E%8B/%E5%BA%8F%E5%88%97%E6%A8%A1%E5%9E%8B/

[wanghenshui]

perf record -e cycles:u -j any,u -o perf.data -- gnome-text-editor

you can do this for any of the binaries

perf2bolt -p perf.data -o perf.fdata ~/.jhbuild/lib/libpango-1.0.so

llvm-bolt ~/.jhbuild/lib/libpango-1.0.so -o libpango-1.0.so.bolt -data=perf.fdata -reorder-blocks=ext-tsp -reorder-functions=hfsort -split-functions -split-all-cold -split-eh -dyno-stats

mv libpango-1.0.so.bolt ~/.jhbuild/lib/libpango-1.0.so

[wanghenshui]

Register Spills 寄存器压力 。重写，合并。需要报告

依赖链 降低依赖，interleave， 使用小buffer增加局部性

https://johnnysswlab.com/performance-debugging-with-llvm-mca-simulating-the-cpu/
https://johnnysswlab.com/when-vectorization-hits-the-memory-wall-investigating-the-avx2-memory-gather-instruction/
https://johnnysswlab.com/the-price-of-dynamic-memory-allocation/
https://johnnysswlab.com/the-price-of-dynamic-memory-memory-access/
https://johnnysswlab.com/the-true-price-of-virtual-functions-in-c/
https://johnnysswlab.com/2-minute-read-class-size-member-layout-and-speed/
https://johnnysswlab.com/make-your-programs-run-faster-by-better-using-the-data-cache/
https://johnnysswlab.com/how-branches-influence-the-performance-of-your-code-and-what-can-you-do-about-it/
https://johnnysswlab.com/make-your-programs-run-faster-avoid-function-calls/
https://johnnysswlab.com/make-your-programs-run-faster-avoid-expensive-instructions/
https://johnnysswlab.com/making-your-program-run-faster-in-a-multithreaded-environment/
https://johnnysswlab.com/link-time-optimizations-new-way-to-do-compiler-optimizations/
https://johnnysswlab.com/tune-your-programs-speed-with-profile-guided-optimizations/
https://johnnysswlab.com/loop-optimizations-taking-matters-into-your-hands/
https://johnnysswlab.com/loop-optimizations-how-does-the-compiler-do-it/
https://johnnysswlab.com/crash-course-introduction-to-parallelism-the-algorithms/
https://johnnysswlab.com/crash-course-introduction-to-parallelism-simd-parallelism/
https://johnnysswlab.com/crash-course-introduction-to-parallelism-multithreading/
https://johnnysswlab.com/multitime-a-small-utility-to-measure-your-programs-runtime/
https://johnnysswlab.com/speedscope-visualize-what-your-program-is-doing-and-where-it-is-spending-time/
https://johnnysswlab.com/hardware-performance-counters-the-easy-way-quickstart-likwid-perfctr/
https://johnnysswlab.com/performance-debugging-with-llvm-mca-simulating-the-cpu/
https://johnnysswlab.com/fiya-flamegraphs-in-your-app/
https://johnnysswlab.com/speeding-up-convergence-loops-or-on-vectorization-and-precision-control/
https://johnnysswlab.com/the-memory-subsystem-from-the-viewpoint-of-software-how-memory-subsystem-effects-software-performance-1-2/