From: Olof Johansson <olof@lixom.net>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>
Subject: Re: [PATCH 1/5] powerpc: consolidate feature fixup code
Date: Fri, 13 Oct 2006 21:01:47 -0500 [thread overview]
Message-ID: <20061013210147.4c904ad1@localhost.localdomain> (raw)
In-Reply-To: <1160779006.4792.269.camel@localhost.localdomain>
On Sat, 14 Oct 2006 08:36:46 +1000 Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
>
> > You can advance the pointer with L1_CACHE_BYTES/sizeof(int) per
> > iteration in the second loop here.
>
> Yeah, I suppose so. Though I'm not 100% confident we get L1_CACHE_BYTES
> on all cpus, for example, PA6T is 64 bytes ;) We could use
> cur_cpu_spec->icache_bsize but that would involve ugly RELOC's to get it
> right on 32 bits. I decided not to care for now.
Ugh, yeah, I remember this when I did the patches but forgot about it
now. L1_CACHE_BYTES is used in a number of places, but overall used as
the largest value needed to bump between lines to avoid false sharing.
The other early places seems to have used hardcoded constants. I guess
it's better to just loop over every word like you're already doing. It
still avoids a barrier on every iteration.
-Olof
next prev parent reply other threads:[~2006-10-14 2:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-13 8:04 [PATCH 1/5] powerpc: consolidate feature fixup code Benjamin Herrenschmidt
2006-10-13 16:54 ` Olof Johansson
2006-10-13 22:36 ` Benjamin Herrenschmidt
2006-10-14 2:01 ` Olof Johansson [this message]
2006-10-14 1:42 ` Stephen Rothwell
2006-10-14 1:58 ` Olof Johansson
2006-10-14 2:11 ` Olof Johansson
2006-10-16 4:51 ` Benjamin Herrenschmidt
2006-10-16 6:25 ` [PATCH 1/5] powerpc: consolidate feature fixup code #2 Benjamin Herrenschmidt
-- strict thread matches above, loose matches on Subject: below --
2006-10-20 1:47 [PATCH 1/5] powerpc: consolidate feature fixup code Benjamin Herrenschmidt
2006-10-20 2:00 ` Olof Johansson
2006-10-23 10:40 ` Paul Mackerras
2006-10-23 21:12 ` Benjamin Herrenschmidt
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