Thread (12 messages) flat view 12 messages, 2 authors, 2011-07-07

Re: [PATCH v2 net-next af-packet 1/2] Enhance af-packet to provide (near zero)lossless packet capture functionality.

From: David Miller <davem@davemloft.net>
Date: 2011-07-07 13:12:10
Also in: lkml

From: chetan loke <redacted>
Date: Thu, 7 Jul 2011 09:04:58 -0400
On Thu, Jul 7, 2011 at 3:13 AM, David Miller [off-list ref] wrote:
quoted
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.
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