Messages in this thread | | | Subject | Re: VFS scalability (was: [rfc] lockless pagecache) | From | Andi Kleen <> | Date | 27 Jun 2005 09:13:27 +0200 |
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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.
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