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authorNick Piggin <npiggin@kernel.dk>2011-01-07 06:50:08 (GMT)
committerNick Piggin <npiggin@kernel.dk>2011-01-07 06:50:32 (GMT)
commite1bb57826381199cc79fbf44e9dfeee58fc7b339 (patch)
treeb2f5edeebc568c3fff4afd799801e9e605b99efc
parent4b936885ab04dc6e0bb0ef35e0e23c1a7364d9e5 (diff)
downloadlinux-e1bb57826381199cc79fbf44e9dfeee58fc7b339.tar.xz
fs: prefetch inode data in dcache lookup
This makes single threaded git diff -1.25% +/- 0.05% elapsed time on my 2s12c24t Westmere system, and -0.86% +/- 0.05% on my 2s8c Barcelona, by prefetching the important first cacheline of the inode in while we do the actual name compare and other operations on the dentry. There was no measurable slowdown in the single file stat case, or the creat case (where negative dentries would be common). Signed-off-by: Nick Piggin <npiggin@kernel.dk>
-rw-r--r--fs/dcache.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 9e6e6db..2a4ce7d 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1793,6 +1793,9 @@ seqretry:
tlen = dentry->d_name.len;
tname = dentry->d_name.name;
i = dentry->d_inode;
+ prefetch(tname);
+ if (i)
+ prefetch(i);
/*
* This seqcount check is required to ensure name and
* len are loaded atomically, so as not to walk off the