From: Jim Paris <jim@jtan.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Guy <bugzilla@watkins-home.com>,
'Neil Brown' <neilb@cse.unsw.edu.au>,
linux-raid@vger.kernel.org
Subject: Re: RAID-6: help wanted
Date: Fri, 29 Oct 2004 15:21:32 -0400 [thread overview]
Message-ID: <20041029192132.GA10079@jim.sh> (raw)
In-Reply-To: <41829423.2080201@zytor.com>
> >I think they can both be updated with read-modify-write:
> >
> >P' = P + D_n + D_n'
> >Q' = Q + g^n * D_n + g^n * D_n'
>
> It's not a matter of cache-trashing, it's a matter of the fact that very
> few CPUs have any form of parallel table lookup. It could be done with
> dynamic code generation, but that's a whole ball of wax on its own.
Why dynamic? Are there problems with just pregenerating all 256
optimized codepaths?
-jim
next prev parent reply other threads:[~2004-10-29 19:21 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-23 23:46 RAID-6: help wanted H. Peter Anvin
2004-10-24 5:26 ` Brad Campbell
2004-10-24 6:46 ` Jim Paris
[not found] ` <417B546C.3050706@zytor.com>
2004-10-24 7:09 ` H. Peter Anvin
2004-10-24 7:17 ` H. Peter Anvin
2004-10-24 7:18 ` Brad Campbell
2004-10-25 5:41 ` Neil Brown
2004-10-25 6:20 ` Jim Paris
2004-10-25 6:24 ` Neil Brown
2004-10-25 6:33 ` Jim Paris
2004-10-25 14:23 ` H. Peter Anvin
2004-10-27 3:38 ` Neil Brown
2004-10-27 5:23 ` H. Peter Anvin
2004-10-27 6:00 ` Jim Paris
2004-10-27 6:03 ` H. Peter Anvin
2004-10-28 1:17 ` H. Peter Anvin
2004-10-28 16:00 ` Jim Paris
2004-10-28 17:48 ` H. Peter Anvin
2004-10-28 17:49 ` H. Peter Anvin
2004-10-29 0:43 ` Neil Brown
2004-10-29 11:48 ` Jim Paris
2004-10-29 12:56 ` Guy
2004-10-29 18:15 ` Jim Paris
2004-10-29 19:04 ` H. Peter Anvin
2004-10-29 19:21 ` Jim Paris [this message]
2004-10-29 19:33 ` H. Peter Anvin
2004-10-29 20:28 ` Guy
2004-10-29 20:32 ` H. Peter Anvin
2004-10-29 21:21 ` Guy
2004-10-29 21:33 ` H. Peter Anvin
2004-10-29 12:29 ` Guy
2004-10-27 5:56 ` H. Peter Anvin
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