Commit e1bb5782 authored Jan 07, 2011 by Nick Piggin

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>

parent 4b936885

fs/dcache.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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

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