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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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