From: David Miller <davem@davemloft.net>
To: acme@ghostprotocols.net
Cc: xemul@openvz.org, devel@openvz.org, netdev@vger.kernel.org
Subject: Re: [PATCH] Compact sk_stream_mem_schedule() code
Date: Mon, 19 Nov 2007 23:22:45 -0800 (PST) [thread overview]
Message-ID: <20071119.232245.246671296.davem@davemloft.net> (raw)
In-Reply-To: <20071119193059.GA5211@ghostprotocols.net>
From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Date: Mon, 19 Nov 2007 17:30:59 -0200
> Em Mon, Nov 19, 2007 at 03:13:44PM +0300, Pavel Emelyanov escreveu:
> > This function references sk->sk_prot->xxx for many times.
> > It turned out, that there's so many code in it, that gcc
> > cannot always optimize access to sk->sk_prot's fields.
> >
> > After saving the sk->sk_prot on the stack and comparing
> > disassembled code, it turned out that the function became
> > ~10 bytes shorter and made less dereferences (on i386 and
> > x86_64). Stack consumption didn't grow.
> >
> > Besides, this patch drives most of this function into the
> > 80 columns limit.
> >
> > Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
>
> I wonder if making it 'const struct proto *prot = sk->sk_prot;'
>
> would make any difference.
Such experiments are always useful, but I doubt there will
be substantial gains in this case.
> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
I've applied the patch, thanks Pavel.
prev parent reply other threads:[~2007-11-20 7:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-19 12:13 [PATCH] Compact sk_stream_mem_schedule() code Pavel Emelyanov
2007-11-19 19:30 ` Arnaldo Carvalho de Melo
2007-11-20 7:22 ` David Miller [this message]
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