forked from luck/tmp_suning_uos_patched
7bcd3f34e2
They cause quite bad performance regressions on Netburst This is temporary until we can get new optimized functions for these CPUs. This undoes changes that were done in 2.6.15 and in 2.6.16-rc1, essentially bringing the code back to 2.6.14 level. Only change is I renamed the X86_FEATURE_K8_C flag to X86_FEATURE_REP_GOOD and fixed the check for the flag and also fixed some comments. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
51 lines
791 B
ArmAsm
51 lines
791 B
ArmAsm
/*
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* Zero a page.
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* rdi page
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*/
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.globl clear_page
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.p2align 4
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clear_page:
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xorl %eax,%eax
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movl $4096/64,%ecx
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.p2align 4
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.Lloop:
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decl %ecx
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#define PUT(x) movq %rax,x*8(%rdi)
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movq %rax,(%rdi)
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PUT(1)
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PUT(2)
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PUT(3)
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PUT(4)
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PUT(5)
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PUT(6)
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PUT(7)
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leaq 64(%rdi),%rdi
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jnz .Lloop
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nop
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ret
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clear_page_end:
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/* Some CPUs run faster using the string instructions.
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It is also a lot simpler. Use this when possible */
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#include <asm/cpufeature.h>
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.section .altinstructions,"a"
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.align 8
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.quad clear_page
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.quad clear_page_c
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.byte X86_FEATURE_REP_GOOD
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.byte clear_page_end-clear_page
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.byte clear_page_c_end-clear_page_c
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.previous
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.section .altinstr_replacement,"ax"
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clear_page_c:
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movl $4096/8,%ecx
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xorl %eax,%eax
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rep
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stosq
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ret
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clear_page_c_end:
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.previous
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