ORATEA

gcc的优化选项测试

[oracle@dw_testdb sunwg]$ gcc -O2 -Wall -o convert_code convert_code.c
[oracle@dw_testdb sunwg]$ time ./convert_code from_code=gbk to_code=gbk in_file=0.dat out_file=0_gbk_1.dat convert_type=byte

real 3m4.633s
user 2m36.525s
sys 0m6.121s
[oracle@dw_testdb sunwg]$ gcc -O1 -Wall -o convert_code convert_code.c
[oracle@dw_testdb sunwg]$ time ./convert_code from_code=gbk to_code=gbk in_file=0.dat out_file=0_gbk_1.dat convert_type=byte

real 1m15.513s
user 0m47.796s
sys 0m5.792s
[oracle@dw_testdb sunwg]$ gcc -O2 -Wall -o convert_code convert_code.c
[oracle@dw_testdb sunwg]$ time ./convert_code from_code=gbk to_code=gbk in_file=0.dat out_file=0_gbk_1.dat convert_type=byte

real 1m15.675s
user 0m44.579s
sys 0m5.851s
[oracle@dw_testdb sunwg]$ gcc -O3 -Wall -o convert_code convert_code.c
[oracle@dw_testdb sunwg]$ time ./convert_code from_code=gbk to_code=gbk in_file=0.dat out_file=0_gbk_1.dat convert_type=byte

从上面的结果能看出来，开启gcc的优化选项的效果还是很明显的，速度提升了一倍以上。
能提升这么多，估计和我写的程序比较烂有关系，哈哈
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