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    SubjectRe: [RFC] Use RCU for tcp_ehash lookup
    On Wed, Sep 01, 2004 at 05:06:41PM +0530, Srivatsa Vaddagiri wrote:
    > | 2.6.8.1 | 2.6.8.1 + my patch
    > -------------------------------------------------------------------------------
    > Average cycles | |
    > spent in | |
    > __tcp_v4_lookup_established | 2970.65 | 668.227
    > | (~3.3 micro-seconds) | (~0.74 microseconds)
    > -------------------------------------------------------------------------------
    >
    > This repesents improvement by a factor of 77.5%!

    Nice.

    >
    >
    > >
    > > And it should also fix the performance problems with
    > > cat /proc/net/tcp on ppc64/ia64 for large hash tables because the rw locks
    > > are gone.
    >
    > But spinlocks are in! Would that still improve the performance compared to rw
    > locks? (See me earlier note where I have explained that lookup done for
    > /proc/net/tcp is _not_ lock-free yet).

    Yes, spinlocks are much faster than rwlocks.

    -Andi

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