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| author | mjg <mjg@FreeBSD.org> | 2016-12-31 13:23:28 +0000 |
|---|---|---|
| committer | mjg <mjg@FreeBSD.org> | 2016-12-31 13:23:28 +0000 |
| commit | f3626becbf8107ecc4188b9c807fa02b06527c46 (patch) | |
| tree | e86ac079438060bda57423b36c2d2caa4c113256 | |
| parent | 861927d8f804e958ca0225577e0a647f2e675550 (diff) | |
| download | FreeBSD-src-f3626becbf8107ecc4188b9c807fa02b06527c46.zip FreeBSD-src-f3626becbf8107ecc4188b9c807fa02b06527c46.tar.gz | |
MFC r303583:
amd64: implement pagezero using rep stos
The current implementation uses non-temporal writes. This turns out to
be detrimental to performance if the page is used shortly after, which
is the typical case with page faults.
Switch to rep stos.
| -rw-r--r-- | sys/amd64/amd64/support.S | 13 |
1 files changed, 3 insertions, 10 deletions
diff --git a/sys/amd64/amd64/support.S b/sys/amd64/amd64/support.S index bc23e90..c8b6253 100644 --- a/sys/amd64/amd64/support.S +++ b/sys/amd64/amd64/support.S @@ -65,17 +65,10 @@ END(bzero) /* Address: %rdi */ ENTRY(pagezero) PUSH_FRAME_POINTER - movq $-PAGE_SIZE,%rdx - subq %rdx,%rdi + movq $PAGE_SIZE/8,%rcx xorl %eax,%eax -1: - movnti %rax,(%rdi,%rdx) - movnti %rax,8(%rdi,%rdx) - movnti %rax,16(%rdi,%rdx) - movnti %rax,24(%rdi,%rdx) - addq $32,%rdx - jne 1b - sfence + rep + stosq POP_FRAME_POINTER ret END(pagezero) |
