From: Francois Romieu <romieu@fr.zoreil.com>
To: Don Fry <pcnet32@verizon.net>
Cc: John Dykstra <john.dykstra1@gmail.com>,
David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, jeff@garzik.org
Subject: Re: [PATCH net-next-2.6] pcnet32: Remove pointless memory barriers
Date: Thu, 30 Apr 2009 00:29:06 +0200 [thread overview]
Message-ID: <20090429222906.GA16498@electric-eye.fr.zoreil.com> (raw)
In-Reply-To: <1241025057.17018.7.camel@localhost.localdomain>
Don Fry <pcnet32@verizon.net> :
> My original NAPI implementation did not have the mmiowb() but it was
> added because of some comments from Francois Romeiu (2006-06-29/30). I
> do not know if they are required or not. My feeling was/is that they
> are not as the writes are flushed with the unlocking primitives.
> However that is not based on knowledge, just "feeling".
(not sure if anyone should care about the loss of performance on x86
for a memory barrier near a couple of PCI I/O accesses but...)
I take back my comment from 2006 as I did not notice that there were
PCI I/O space accesses only.
--
Ueimor
next prev parent reply other threads:[~2009-04-29 22:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-28 19:07 [PATCH net-next-2.6] pcnet32: Remove pointless memory barriers John Dykstra
2009-04-29 5:16 ` David Miller
2009-04-29 13:48 ` John Dykstra
2009-04-29 17:10 ` Don Fry
2009-04-29 19:07 ` John Dykstra
2009-04-29 22:29 ` Francois Romieu [this message]
2009-04-30 0:09 ` Don Fry
2009-04-30 0:16 ` John Dykstra
2009-04-30 0:21 ` David Miller
2009-04-30 0:19 ` David Miller
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