Date: Wed, 18 Sep 2019 14:38:42 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r352485 - stable/12/sys/arm64/arm64 Message-ID: <201909181438.x8IEcgMT060657@repo.freebsd.org>
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Author: alc Date: Wed Sep 18 14:38:42 2019 New Revision: 352485 URL: https://svnweb.freebsd.org/changeset/base/352485 Log: MFC r349768 Restructure cache_handle_range to avoid repeated barriers. Specifically, restructure cache_handle_range so that all of the data cache operations are performed before any instruction cache operations. Then, we only need one barrier between the data and instruction cache operations and one barrier after the instruction cache operations. On an Amazon EC2 a1.2xlarge instance, this simple change reduces the time for a "make -j8 buildworld" by 9%. Modified: stable/12/sys/arm64/arm64/cpufunc_asm.S Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/arm64/arm64/cpufunc_asm.S ============================================================================== --- stable/12/sys/arm64/arm64/cpufunc_asm.S Wed Sep 18 14:27:09 2019 (r352484) +++ stable/12/sys/arm64/arm64/cpufunc_asm.S Wed Sep 18 14:38:42 2019 (r352485) @@ -47,7 +47,7 @@ __FBSDID("$FreeBSD$"); /* * Macro to handle the cache. This takes the start address in x0, length - * in x1. It will corrupt x0, x1, x2, and x3. + * in x1. It will corrupt x0, x1, x2, x3, and x4. */ .macro cache_handle_range dcop = 0, ic = 0, icop = 0 .if \ic == 0 @@ -60,17 +60,23 @@ __FBSDID("$FreeBSD$"); and x2, x0, x4 /* Get the low bits of the address */ add x1, x1, x2 /* Add these to the size */ bic x0, x0, x4 /* Clear the low bit of the address */ -1: - dc \dcop, x0 - dsb ish .if \ic != 0 - ic \icop, x0 - dsb ish + mov x2, x0 /* Save the address */ + mov x4, x1 /* Save the size */ .endif +1: + dc \dcop, x0 add x0, x0, x3 /* Move to the next line */ subs x1, x1, x3 /* Reduce the size */ b.hi 1b /* Check if we are done */ + dsb ish .if \ic != 0 +2: + ic \icop, x2 + add x2, x2, x3 /* Move to the next line */ + subs x4, x4, x3 /* Reduce the size */ + b.hi 2b /* Check if we are done */ + dsb ish isb .endif .endm
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