Date: Sun, 5 Apr 2015 05:07:25 +0000 (UTC) From: Eitan Adler <eadler@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r281100 - head/sys/amd64/amd64 Message-ID: <201504050507.t3557PBR096782@svn.freebsd.org>
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Author: eadler Date: Sun Apr 5 05:07:24 2015 New Revision: 281100 URL: https://svnweb.freebsd.org/changeset/base/281100 Log: head/sys/amd64/amd64/support.S: unroll loop unroll the loop in ENTRY(pagezero) acc' to the submitter this results in a reproducible 1% perf improvement under buildworld like workload I validated correctness and run-testing, but not performance impact Submitted by: lidl@pix.net Reviewed by: adrian PR: 199151 MFC After: 1 month Modified: head/sys/amd64/amd64/support.S Modified: head/sys/amd64/amd64/support.S ============================================================================== --- head/sys/amd64/amd64/support.S Sun Apr 5 05:00:25 2015 (r281099) +++ head/sys/amd64/amd64/support.S Sun Apr 5 05:07:24 2015 (r281100) @@ -73,7 +73,11 @@ ENTRY(pagezero) movnti %rax,8(%rdi,%rdx) movnti %rax,16(%rdi,%rdx) movnti %rax,24(%rdi,%rdx) - addq $32,%rdx + movnti %rax,32(%rdi,%rdx) + movnti %rax,40(%rdi,%rdx) + movnti %rax,48(%rdi,%rdx) + movnti %rax,56(%rdi,%rdx) + addq $64,%rdx jne 1b sfence POP_FRAME_POINTER
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