Date: Wed, 2 Mar 2011 00:24:07 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/amd64/amd64 pmap.c Message-ID: <201103020024.p220ON86017450@repoman.freebsd.org>
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alc 2011-03-02 00:24:07 UTC
FreeBSD src repository
Modified files:
sys/amd64/amd64 pmap.c
Log:
SVN rev 219157 on 2011-03-02 00:24:07Z by alc
Make a change to the implementation of the direct map to improve performance
on processors that support 1 GB pages. Specifically, if the end of physical
memory is not aligned to a 1 GB page boundary, then map the residual
physical memory with multiple 2 MB page mappings rather than a single 1 GB
page mapping. When a 1 GB page mapping is used for this residual memory,
access to the memory is slower than when multiple 2 MB page mappings are
used. (I suspect that the reason for this slowdown is that the TLB is
actually being loaded with 4 KB page mappings for the residual memory.)
X-MFC after: r214425
Revision Changes Path
1.719 +28 -29 src/sys/amd64/amd64/pmap.c
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