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    SubjectRe: VFS scalability (was: [rfc] lockless pagecache)
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    Nick Piggin <nickpiggin@yahoo.com.au> writes:

    > This is with the filesystem mounted as noatime, so I can't work
    > out why update_atime is so high on the list. I suspect maybe a
    > false sharing issue with some other fields.

    Did all the 64CPUs write to the same file?

    Then update_atime was just the messenger - it is the first function
    to read the inode so it eats the cache miss overhead.

    Maybe adding a prefetch for it at the beginning of sys_read()
    might help, but then with 64CPUs writing to parts of the inode
    it will always thrash no matter how many prefetches.

    -Andi
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