From: Peter Tyser <ptyser@xes-inc.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH V2 1/3] memcpy: copy one word at a time if possible
Date: Thu, 08 Oct 2009 11:30:56 -0500 [thread overview]
Message-ID: <1255019456.9100.1140.camel@localhost.localdomain> (raw)
In-Reply-To: <20091008160026.GA9077@mail.gnudd.com>
On Thu, 2009-10-08 at 18:00 +0200, Alessandro Rubini wrote:
> > No interest in the suggestion to not require count to be an exact
> > multiple of 4/8?
>
> Actually, I wrote about that in my patch 0/3.
Sorry, I should have read more thoroughly.
> > I don't think it would be that hard to update the logic accordingly
> > and this would let your code be utilized much more often, especially
> > if/when we run on a 64-bit machine.
>
> That's true, but I think the most important case is lcd scrolling,
> where it's usually a big power of two -- that's where we had the #ifdef,
> so the problem was known, I suppose.
I think the most important case for *you* is lcd scrolling, but for 99%
of everyone else, it isn't at all:) memcpy() and memset() are used 100
times more often in non-lcd related code and most boards don't even have
LCDs. In my opinion, we shouldn't be fixing/bloating common code for 1
outlying scenario, we should be trying to improve it for common cases.
> Currently, I don't even know if this is going to be picked up, so I
> don't want to go too far -- and in that case I would like to measure
> things and be able to test for stupid bugs, so it takes time.
Sure, I understand where you're coming from. FWIW, if people don't want
to pick this up as it affects lots of people, you could always add an
architecture-specific memcpy/memset implementation.
> If there's interest, there's memmov to fix; it's used pretty often and
> it's the same idea as memcpy (well, scrolling should use memmove,
> in theory).
I'll quit pestering, just wanted to put my $.02 in:)
Best,
Peter
next prev parent reply other threads:[~2009-10-08 16:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-08 11:29 [U-Boot] [PATCH V2 0/3] make memcpy and memset faster Alessandro Rubini
2009-10-08 11:30 ` [U-Boot] [PATCH V2 1/3] memcpy: copy one word at a time if possible Alessandro Rubini
2009-10-08 15:12 ` Peter Tyser
2009-10-08 16:00 ` Alessandro Rubini
2009-10-08 16:30 ` Peter Tyser [this message]
2009-10-08 18:23 ` Alessandro Rubini
2009-10-08 19:09 ` Peter Tyser
2009-10-08 19:17 ` Alessandro Rubini
2009-10-08 20:40 ` Wolfgang Denk
2009-10-08 20:47 ` Wolfgang Denk
2009-10-08 19:14 ` Mike Frysinger
2009-10-08 20:44 ` Wolfgang Denk
2009-10-09 4:42 ` Chris Moore
2009-10-09 10:11 ` Mark Jackson
2009-10-09 10:26 ` Mike Frysinger
2009-10-11 7:06 ` Chris Moore
2009-10-09 11:12 ` Wolfgang Denk
2009-10-08 11:30 ` [U-Boot] [PATCH V2 2/3] memset: fill " Alessandro Rubini
2009-10-08 20:46 ` Wolfgang Denk
2009-10-08 11:30 ` [U-Boot] [PATCH V2 3/3] lcd: remove '#if 0' 32-bit scroll, now memcpy does it Alessandro Rubini
2009-11-22 22:34 ` Wolfgang Denk
2009-11-24 23:04 ` Anatolij Gustschin
2009-10-08 20:36 ` [U-Boot] [PATCH V2 0/3] make memcpy and memset faster Wolfgang Denk
2009-10-08 21:30 ` Mike Frysinger
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