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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Karsten Keil <kkeil@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org, isdn4linux@listserv.isdn4linux.de,
	"Andreas.Eversberg" <Andreas.Eversberg@versatel.de>
Subject: Re: [PATCH 3/4] Fix remaining big endian issue of hfcmulti
Date: Wed, 06 Aug 2008 07:45:53 +1000	[thread overview]
Message-ID: <1217972753.24157.204.camel@pasglop> (raw)
In-Reply-To: <20080805210239.GB6052@pingi.kke.suse.de>


> static void
> my_out32(struct card *c, u_int offset, u-int data) 
> {
> 	if (c->mode == MMIO) {
> 		...
> 	} else {
> 		...
> 	}
> }
> 
> or use 2 function, one for the MMIO and one for the PIO model and then use
> indirect calls (like c->my_out32(...)) ?

The former is more ugly but slightly faster on some archs.

Indirect function calls tend to be slightly slower than an if / else
statement that can be more easily predicted by the processor.

But in the case of IOs, it's not going to be a big deal, -especially- if
you use the _rep forms for data transfers (and thus don't do an indirect
call for each read/write). So it's totally up to you.

Cheers,
Ben.



  parent reply	other threads:[~2008-08-05 21:46 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-02 14:35 [PATCH 3/4] Fix remaining big endian issue of hfcmulti Karsten Keil
2008-08-04 12:03 ` David Woodhouse
2008-08-04 14:29   ` Karsten Keil
2008-08-05  4:29 ` Benjamin Herrenschmidt
2008-08-05 11:31   ` Karsten Keil
2008-08-05 13:04     ` Benjamin Herrenschmidt
2008-08-05 17:25       ` Karsten Keil
2008-08-05 18:42         ` Linus Torvalds
2008-08-05 21:02           ` Karsten Keil
2008-08-05 21:23             ` Sean MacLennan
2008-08-05 21:37               ` Linus Torvalds
2008-08-05 21:59                 ` Sean MacLennan
2008-08-05 23:04                   ` Benjamin Herrenschmidt
2008-08-05 23:38                     ` Sean MacLennan
2008-08-06  0:18                   ` Karsten Keil
2008-08-06  0:33                     ` Benjamin Herrenschmidt
2008-08-05 21:46               ` Benjamin Herrenschmidt
2008-08-05 21:45             ` Benjamin Herrenschmidt [this message]
2008-08-05 21:43         ` Benjamin Herrenschmidt
  -- strict thread matches above, loose matches on Subject: below --
2008-08-07 11:01 AW: " Andreas.Eversberg
2008-08-07 13:46 ` Karsten Keil

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