<2022-04-07 Thu>

gm benchmark性能比较

仅运行一次缩放图片的话gm-ocl（启用了硬件加速）的速度远小于gm（没有硬件加速，下同），而迭代100次的话，gm-ocl速度高于gm，见：

启用了硬件加速：

[ysouyno@arch gm-ocl]$ gm benchmark -iterations 100 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 100 iter 6.35s user 4.997407s total 20.010 iter/s 15.748 iter/cpu
[ysouyno@arch gm-ocl]$ gm benchmark -iterations 100 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 100 iter 5.99s user 4.873903s total 20.517 iter/s 16.694 iter/cpu
[ysouyno@arch gm-ocl]$ gm benchmark convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1 iter 0.35s user 0.830804s total 1.204 iter/s 2.857 iter/cpu
[ysouyno@arch gm-ocl]$ gm benchmark convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1 iter 0.30s user 0.136360s total 7.334 iter/s 3.333 iter/cpu
[ysouyno@arch gm-ocl]$ gm benchmark convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1 iter 0.29s user 0.814550s total 1.228 iter/s 3.448 iter/cpu
[ysouyno@arch gm-ocl]$ echo $MAGICK_OCL_DEVICE
true
[ysouyno@arch gm-ocl]$

没有启用硬件加速：

[ysouyno@arch ~]$ gm benchmark -iterations 100 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 100 iter 40.57s user 5.829435s total 17.154 iter/s 2.465 iter/cpu
[ysouyno@arch ~]$ gm benchmark -iterations 100 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 100 iter 42.74s user 6.115149s total 16.353 iter/s 2.340 iter/cpu
[ysouyno@arch ~]$ gm benchmark convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1 iter 0.31s user 0.057625s total 17.354 iter/s 3.226 iter/cpu
[ysouyno@arch ~]$ gm benchmark convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1 iter 0.32s user 0.057751s total 17.316 iter/s 3.125 iter/cpu
[ysouyno@arch ~]$ gm benchmark convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1 iter 0.31s user 0.057476s total 17.399 iter/s 3.226 iter/cpu
[ysouyno@arch ~]$ echo $MAGICK_OCL_DEVICE[ysouyno@arch ~]$

从上表看，一百次迭代，启用硬件加速比没有启用硬件加速为：6:40，即1:6.6。

分析：在启用了硬件加速后，gm-ocl每次都将加载~/.cache/ImageMagick/中的镜像，该读取磁盘文件属于慢操作；而gm则没有这种加载时间的影响。当迭代100次时gm-ocl的加载时间比重就缩小了。

如果改成1000次的话，似乎gm-ocl的优势更加明显。

启用了硬件加速：

[ysouyno@arch gm-ocl]$ gm benchmark -iterations 100 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 100 iter 6.02s user 4.814306s total 20.771 iter/s 16.611 iter/cpu
[ysouyno@arch gm-ocl]$ gm benchmark -iterations 1000 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1000 iter 59.54s user 43.377261s total 23.054 iter/s 16.795 iter/cpu
[ysouyno@arch gm-ocl]$ echo $MAGICK_OCL_DEVICE
true
[ysouyno@arch gm-ocl]$

没有启用硬件加速：

[ysouyno@arch ~]$ gm benchmark -iterations 100 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 100 iter 41.49s user 5.985783s total 16.706 iter/s 2.410 iter/cpu
[ysouyno@arch ~]$ gm benchmark -iterations 1000 convert ~/temp/bg1a.jpg -resize 960x540 ~/temp/out.jpg
Results: 8 threads 1000 iter 536.90s user 77.881720s total 12.840 iter/s 1.863 iter/cpu
[ysouyno@arch ~]$ echo $MAGICK_OCL_DEVICE[ysouyno@arch ~]$

从上表看，一千次迭代，启用硬件加速比没有启用硬件加速为：59:536，即1:9。优势明显呀！😃