From: "David Laight" <David.Laight@ACULAB.COM>
To: "David Miller" <davem@davemloft.net>, <rick.jones2@hp.com>
Cc: <cascardo@linux.vnet.ibm.com>, <netdev@vger.kernel.org>,
<yevgenyp@mellanox.co.il>, <ogerlitz@mellanox.com>,
<amirv@mellanox.com>, <brking@linux.vnet.ibm.com>,
<leitao@linux.vnet.ibm.com>, <klebers@linux.vnet.ibm.com>
Subject: RE: [PATCH] mlx4_en: map entire pages to increase throughput
Date: Tue, 17 Jul 2012 13:42:04 +0100 [thread overview]
Message-ID: <AE90C24D6B3A694183C094C60CF0A2F6026B6F8B@saturn3.aculab.com> (raw)
In-Reply-To: <20120716.222903.367603216293954363.davem@davemloft.net>
> > That seems rather extraordinarily low - Power7 is supposed to be a
> > rather high performance CPU. The last time I noticed O(3Gbit/s) on
> > 10G for bulk transfer was before the advent of LRO/GRO - that was in
> > the x86 space though. Is mapping really that expensive with Power7?
>
> Unfortunately, IOMMU mappings are incredibly expensive. I see effects
> like this on Sparc too.
Would there be any mileage in permanently allocating IOMMU
virtual address to the ring entries, then 'just' assigning
the correct physical address during rx/tx setup?
A long time ago it used to be much faster on sparc systems
to receive into a permanently mapped buffer area and then
do a maximally aligned copy into the actual rx buffer.
David
next prev parent reply other threads:[~2012-07-17 12:42 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-16 17:01 [PATCH] mlx4_en: map entire pages to increase throughput Thadeu Lima de Souza Cascardo
2012-07-16 17:27 ` Rick Jones
2012-07-16 19:06 ` Thadeu Lima de Souza Cascardo
2012-07-16 19:06 ` Thadeu Lima de Souza Cascardo
2012-07-16 19:42 ` Rick Jones
2012-07-16 19:42 ` Rick Jones
2012-07-16 20:36 ` Or Gerlitz
2012-07-16 20:36 ` Or Gerlitz
2012-07-16 20:43 ` Or Gerlitz
2012-07-16 20:43 ` Or Gerlitz
2012-07-16 20:57 ` Thadeu Lima de Souza Cascardo
2012-07-16 20:57 ` Thadeu Lima de Souza Cascardo
2012-07-18 14:59 ` Or Gerlitz
2012-07-18 14:59 ` Or Gerlitz
2012-07-16 20:47 ` Thadeu Lima de Souza Cascardo
2012-07-16 20:47 ` Thadeu Lima de Souza Cascardo
2012-07-16 21:08 ` Rick Jones
2012-07-16 21:08 ` Rick Jones
2012-07-17 5:29 ` David Miller
2012-07-17 12:42 ` David Laight [this message]
2012-07-17 12:50 ` David Miller
2012-07-17 13:36 ` David Laight
2012-07-17 13:46 ` David Miller
2012-07-17 13:50 ` Eric Dumazet
2012-07-17 18:17 ` Rick Jones
2012-07-17 20:10 ` Brian King
2012-07-17 20:20 ` David Miller
2012-07-19 17:53 ` David Miller
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