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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: netdev@vger.kernel.org,
	Yevgeny Petrilin <yevgenyp@mellanox.co.il>,
	Eli Cohen <eli@mellanox.co.il>,
	Eli Cohen <eli@dev.mellanox.co.il>,
	linuxppc-dev@lists.ozlabs.org,
	Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Subject: RE: [PATCH] mlx4_en: fix transmit of packages when blue frame isenabled
Date: Sun, 09 Oct 2011 09:28:51 +0200	[thread overview]
Message-ID: <1318145331.29415.372.camel@pasglop> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6D8AE76@saturn3.aculab.com>

On Thu, 2011-10-06 at 15:10 +0100, David Laight wrote:
> horrid...
> 1) I'm not sure the caller expects the buffer to be corrupted.
> 2) It contains a lot of memory cycles.
> 3) It looked from the calls that this code is copying descriptors,
>    so the transfer length is probably 1 or 2 words - so the loop
>    is inefficient.
> 4) ppc doesn't have a fast byteswap instruction (very new gcc might
>    use the byteswapping memery access for the le32_to_cpu() though),
>    so it would be better getting the byteswap done inside
>    __iowrite64_copy() - since that is probably requesting a byteswap
>    anyway.
> OTOH I'm not at all clear about the 64bit xfers....

And it's just plain wrong anyway. You should never have to byteswap a
copy.

Ben.

  parent reply	other threads:[~2011-10-09  7:29 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1317388995-411-1-git-send-email-cascardo@linux.vnet.ibm.com>
     [not found] ` <953B660C027164448AE903364AC447D2235D9A8C@MTLDAG02.mtl.com>
     [not found]   ` <20111003143721.GA3596@oc1711230544.ibm.com>
     [not found]     ` <953B660C027164448AE903364AC447D2235DAA9D@MTLDAG02.mtl.com>
2011-10-03 20:53       ` [PATCH] mlx4_en: fix transmit of packages when blue frame is enabled Thadeu Lima de Souza Cascardo
2011-10-04  6:02         ` Benjamin Herrenschmidt
2011-10-04 20:26           ` Thadeu Lima de Souza Cascardo
2011-10-05  8:15             ` Eli Cohen
2011-10-06 13:57               ` Eli Cohen
2011-10-06 14:10                 ` [PATCH] mlx4_en: fix transmit of packages when blue frame isenabled David Laight
2011-10-07 22:29                   ` Thadeu Lima de Souza Cascardo
2011-10-09  7:28                   ` Benjamin Herrenschmidt [this message]
2011-10-09  7:25                 ` [PATCH] mlx4_en: fix transmit of packages when blue frame is enabled Benjamin Herrenschmidt
2011-10-09  7:35                   ` Eli Cohen
2011-10-09  8:00                     ` Benjamin Herrenschmidt
2011-10-09  8:07                       ` Eli Cohen
2011-10-09  8:38                         ` Benjamin Herrenschmidt
2011-10-09  9:21                           ` Eli Cohen
2011-10-09  9:52                             ` Benjamin Herrenschmidt
2011-10-09 10:30                               ` Eli Cohen
2011-10-10  7:32                                 ` Benjamin Herrenschmidt
2011-10-10 16:42                                   ` [PATCH] mlx4_en: fix endianness with blue frame support Thadeu Lima de Souza Cascardo
2011-10-10 16:46                                     ` Thadeu Lima de Souza Cascardo
2011-10-10 18:10                                       ` David Miller
2011-10-10  8:20                               ` [PATCH] mlx4_en: fix transmit of packages when blue frame is enabled David Laight
2011-10-10  8:29                                 ` Benjamin Herrenschmidt
2011-10-10  8:40                   ` David Laight
2011-10-10  8:47                     ` Eli Cohen
2011-10-10  9:01                       ` Benjamin Herrenschmidt
2011-10-10  9:16                         ` Eli Cohen
2011-10-10  9:24                           ` Benjamin Herrenschmidt
2011-10-10  9:29                             ` Eli Cohen
2011-10-10 10:18                               ` Benjamin Herrenschmidt
2011-10-10  8:53                     ` Benjamin Herrenschmidt
2011-10-09  7:21               ` Benjamin Herrenschmidt
2011-10-09  7:19             ` Benjamin Herrenschmidt

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