From: David Miller <davem@davemloft.net>
To: loke.chetan@gmail.com
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, joe@perches.com,
bhutchings@solarflare.com, shemminger@vyatta.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 net-next af-packet 1/2] Enhance af-packet to provide (near zero)lossless packet capture functionality.
Date: Thu, 07 Jul 2011 06:11:59 -0700 (PDT) [thread overview]
Message-ID: <20110707.061159.1960862007945782564.davem@davemloft.net> (raw)
In-Reply-To: <CAAsGZS4Y=-GSmP+2iYtd+V3RcE2+PpaStBzW7R7TDip7U-rdvA@mail.gmail.com>
From: chetan loke <loke.chetan@gmail.com>
Date: Thu, 7 Jul 2011 09:04:58 -0400
> On Thu, Jul 7, 2011 at 3:13 AM, David Miller <davem@davemloft.net> wrote:
>
>> Get rid of __packed__, it's going to kill performance on RISC
>> platforms. If you use __packed__, regardless of the actual alignment,
>
> The performance boost has been achieved by amortizing the cost of
> static spin-wait/poll and not by shrinking the data-set.
Chetan, if you're implementing something for performance reasons,
getting rid of packed is non-negotiable.
We pass data structures between userspace and the kernel all the
time, and without __packed__. We have mechanisms to ensure the
size of the individual data types, and we have mechanisms to make
sure 64-bit datums get aligned even on x86 (see "aligned_u64" and
friends")
Again, I can't seriously consider your patch if you keep the packed
attribute crap in there.
next prev parent reply other threads:[~2011-07-07 13:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-22 2:10 [PATCH v2 net-next af-packet 0/2] Enhance af-packet to provide (near zero)lossless packet capture functionality Chetan Loke
2011-06-22 2:10 ` [PATCH v2 net-next af-packet 1/2] " Chetan Loke
2011-07-01 22:36 ` David Miller
2011-07-05 14:53 ` chetan loke
2011-07-05 15:01 ` David Miller
2011-07-06 21:45 ` chetan loke
2011-07-07 7:13 ` David Miller
2011-07-07 13:04 ` chetan loke
2011-07-07 13:11 ` David Miller [this message]
2011-06-22 2:10 ` [PATCH v2 net-next af-packet 2/2] " Chetan Loke
2011-06-22 3:02 ` [PATCH v2 net-next af-packet 0/2] " chetan loke
2011-06-22 8:35 ` David Miller
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