編譯時優化的問題,先謝過.

惠繪洋

請教各位大大,在編譯內核時,會以 -march=i686 對機器作出優化,請問若果我是使用pentium4或者athlon能否作出特定機器的優化呢, 如 -march=pentium4 或 -march=amd等呢?

另外,我可以在那找到更多優化的資料呢? 因我在google找過, 但並沒有這方面的資料. 再請指教. thanks.

sakulagi

gcc的man page里有说明，对AMD的CPU也有对应的参数。更深入的我就不清楚了

egret

From gcc manual:

1. Intel 386 and AMD x86-64 Options
   
2. 
   
3.        These -m options are defined for the i386 and x86-64 family of comput-
   
4.        ers:
   
5. 
   
6.        -mtune=cpu-type
   
7.            Tune to cpu-type everything applicable about the generated code,
   
8.            except for the ABI and the set of available instructions.  The
   
9.            choices for cpu-type are:
   
10. 
    
11.            i386
    
12.                Original Intel's i386 CPU.
    
13. 
    
14.            i486
    
15.                Intel's i486 CPU.  (No scheduling is implemented for this
    
16.                chip.)
    
17. 
    
18.            i586, pentium
    
19.                Intel Pentium CPU with no MMX support.
    
20. 
    
21.            pentium-mmx
    
22.                Intel PentiumMMX CPU based on Pentium core with MMX instruction
    
23.                set support.
    
24. 
    
25.            i686, pentiumpro
    
26.                Intel PentiumPro CPU.
    
27. 
    
28.            pentium2
    
29.                Intel Pentium2 CPU based on PentiumPro core with MMX instruc-
    
30.                tion set support.
    
31. 
    
32.            pentium3, pentium3m
    
33.                Intel Pentium3 CPU based on PentiumPro core with MMX and SSE
    
34.                instruction set support.
    
35. 
    
36.            pentium-m
    
37.                Low power version of Intel Pentium3 CPU with MMX, SSE and SSE2
    
38.                instruction set support.         Used by Centrino notebooks.
    
39. 
    
40.            pentium4, pentium4m
    
41.                Intel Pentium4 CPU with MMX, SSE and SSE2 instruction set sup-
    
42.                port.
    
43. 
    
44.            prescott
    
45.                Improved version of Intel Pentium4 CPU with MMX, SSE, SSE2 and
    
46.                SSE3 instruction set support.
    
47. 
    
48.            nocona
    
49.                Improved version of Intel Pentium4 CPU with 64-bit extensions,
    
50.                MMX, SSE, SSE2 and SSE3 instruction set support.
    
51. 
    
52.            k6  AMD K6 CPU with MMX instruction set support.
    
53. 
    
54.            k6-2, k6-3
    
55.                Improved versions of AMD K6 CPU with MMX and 3dNOW! instruction
    
56.                set support.
    
57. 
    
58.            athlon, athlon-tbird
    
59.                AMD Athlon CPU with MMX, 3dNOW!, enhanced 3dNOW! and SSE
    
60.                prefetch instructions support.
    
61. 
    
62.            athlon-4, athlon-xp, athlon-mp
    
63.                Improved AMD Athlon CPU with MMX, 3dNOW!, enhanced 3dNOW! and
    
64.                full SSE instruction set support.
    
65. 
    
66.            k8, opteron, athlon64, athlon-fx
    
67.                AMD K8 core based CPUs with x86-64 instruction set support.
    
68.                (This supersets MMX, SSE, SSE2, 3dNOW!, enhanced 3dNOW! and
    
69.                64-bit instruction set extensions.)
    
70. 
    
71.            winchip-c6
    
72.                IDT Winchip C6 CPU, dealt in same way as i486 with additional
    
73.                MMX instruction set support.
    
74. 
    
75.            winchip2
    
76.                IDT Winchip2 CPU, dealt in same way as i486 with additional MMX
    
77.                and 3dNOW!  instruction set support.
    
78. 
    
79.            c3  Via C3 CPU with MMX and 3dNOW!  instruction set support.         (No
    
80.                scheduling is implemented for this chip.)
    
81. 
    
82.            c3-2
    
83.                Via C3-2 CPU with MMX and SSE instruction set support.  (No
    
84.                scheduling is implemented for this chip.)
    
85. 
    
86.            While picking a specific cpu-type will schedule things appropri-
    
87.            ately for that particular chip, the compiler will not generate any
    
88.            code that does not run on the i386 without the -march=cpu-type
    
89.            option being used.
    
90. 
    
91.        -march=cpu-type
    
92.            Generate instructions for the machine type cpu-type.         The choices
    
93.            for cpu-type are the same as for -mtune.  Moreover, specifying
    
94.            -march=cpu-type implies -mtune=cpu-type.

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mocou

配置参数可以优化，一般的ｌｉｎｕｘ都做好了，
可以上gentoo社区找找，我记得有这方面的资料

egret

不过编译内核选不同的Processor family和设置gcc的编译选项是不大一样的。除非你像用Gentoo那样，所以软件都用编译的方式来安装，设置gcc的编译选项是优化不了系统的。

惠繪洋

先謝謝各位的指教.小弟明白了,再嘗試學習.
egret 的資料很詳細呢, 請問在那找到的呢. thx

egret

[quote]原帖由 "惠繪洋"]egret 的資料很詳細呢, 請問在那找到的呢. thx[/quote 发表：

1. $ man gcc

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:wink:

sakulagi

man gcc

就可以看到那段话了

惠繪洋

[quote]原帖由 "egret"]wink:[/quote 发表：


Thanks, 我只上google不停地找它相關的資料, 一時不懂找找man gcc.