Re: [Bug #11308] tbench regression on each kernel release from 2.6.22 -> 2.6.28

David Miller
2008-11-21T09:05:08Z

From: Eric Dumazet <dada1-fPLkHRcR87vqlBn2x/YWAg@public.gmane.org>
Date: Fri, 21 Nov 2008 09:51:32 +0100

> Now, I wish sockets and pipes not going through dcache, not tbench affair
> of course but real workloads...
>
> running 8 processes on a 8 way machine doing a
>
> for (;;)
> close(socket(AF_INET, SOCK_STREAM, 0));
>
> is slow as hell, we hit so many contended cache lines ...
>
> ticket spin locks are slower in this case (dcache_lock for example
> is taken twice when we allocate a socket(), once in d_alloc(), another one
> in d_instantiate())

As you of course know, this used to be a ton worse. At least now
these things are unhashed. :)