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authorPhil Carmody <ext-phil.2.carmody@nokia.com>2010-08-19 15:20:37 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-09-02 15:31:36 +0100
commit5333a3de3cdd739ec4f6d501f5f6d09bab7ff919 (patch)
tree3c3c2a746c219660f1401f1172d1bdfee3d8a931
parent09e56a2d076c2afb2a1932ae4283e10ef2d26ef3 (diff)
downloadop-kernel-dev-5333a3de3cdd739ec4f6d501f5f6d09bab7ff919.zip
op-kernel-dev-5333a3de3cdd739ec4f6d501f5f6d09bab7ff919.tar.gz
ARM: 6341/1: unwind - optimise linked-list searches for modules
With several sections per module, and dozens of modules, the searches down the linked list of sections would dominate the lookup time, dwarfing any savings from the binary search within the section. A simple move-to-front optimisation exploits the commonality of the code paths taken, and in simple real-world tests reduces the number of steps in the search to barely more than 1. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/kernel/unwind.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index dd81a91..2a16176 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -146,6 +146,8 @@ static struct unwind_idx *unwind_find_idx(unsigned long addr)
addr < table->end_addr) {
idx = search_index(addr, table->start,
table->stop - 1);
+ /* Move-to-front to exploit common traces */
+ list_move(&table->list, &unwind_tables);
break;
}
}
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