From: Joakim Tjernlund <joakim.tjernlund@transmode.se>
To: "George Spelvin" <linux@horizon.com>
Cc: akpm@linux-foundation.org, fzago@systemfabricworks.com,
linux-kernel@vger.kernel.org, rpearson@systemfabricworks.com
Subject: Re: [PATCH] add slice by 8 algorithm to crc32.c
Date: Mon, 8 Aug 2011 13:11:14 +0200 [thread overview]
Message-ID: <OFEA1BD2B2.B2A7F07F-ONC12578E6.003D368C-C12578E6.003D7468@transmode.se> (raw)
In-Reply-To: <20110808105201.25396.qmail@science.horizon.com>
"George Spelvin" <linux@horizon.com> wrote on 2011/08/08 12:52:01:
>
> > I prefer to keep the current code which (at the time) generated good code
> > for at least ppc:
> > /* Align it */
> > if (unlikely((long)buf & 3 && len)) {
> > do {
> > DO_CRC(*buf++);
> > } while ((--len) && ((long)buf)&3);
> > }
>
> Ah, I was looking at fzago's initial patch; I hadn't realized you'd
> tweaked it. That's pretty much what I was talking about.
>
> Would
> if (unlikely((long)buf & 3) && len) {
>
> give the compiler better hints? len != 0 is awfully
> likely, actually.
Doesn't matter on ppc(gcc 4.4.4). The whole while loop is moved out of line
in both cases and the generated asm is identical.
next prev parent reply other threads:[~2011-08-08 11:11 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-08 9:28 [PATCH] add slice by 8 algorithm to crc32.c George Spelvin
2011-08-08 10:31 ` Joakim Tjernlund
2011-08-08 10:52 ` George Spelvin
2011-08-08 11:11 ` Joakim Tjernlund [this message]
2011-08-08 17:04 ` Bob Pearson
[not found] ` <OFEA1BD2B2.B2A7F07F-ONC12578E6.003D368C-C12578E6.003D7468@LocalDomain>
2011-08-08 11:24 ` Joakim Tjernlund
2011-08-08 11:42 ` Joakim Tjernlund
2011-08-08 12:54 ` George Spelvin
2011-08-08 17:01 ` Bob Pearson
2011-08-08 20:45 ` George Spelvin
2011-08-08 22:21 ` Bob Pearson
2011-08-08 16:54 ` Bob Pearson
2011-08-08 16:50 ` Bob Pearson
[not found] <OF4AE0115F.3AA5397E-ONC12578DF.002EC6DF-C12578DF.003348E5@transmode.se>
2011-08-02 21:14 ` Bob Pearson
2011-08-02 21:19 ` Bob Pearson
2011-08-04 11:54 ` Joakim Tjernlund
2011-08-04 18:53 ` Bob Pearson
2011-08-05 9:22 ` Joakim Tjernlund
2011-08-05 15:51 ` Bob Pearson
2011-08-08 7:11 ` Joakim Tjernlund
2011-08-05 17:27 ` Bob Pearson
2011-08-08 7:15 ` Joakim Tjernlund
[not found] ` <OF14136E0E.3F2388EF-ONC12578E3.00301969-C12578E3.00338524@LocalDomain>
2011-08-05 13:34 ` Joakim Tjernlund
-- strict thread matches above, loose matches on Subject: below --
2011-07-20 22:19 frank zago
2011-07-28 22:16 ` Andrew Morton
2011-07-29 1:47 ` Bob Pearson
2011-08-01 19:39 ` Andrew Morton
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