From: Andi Kleen <ak@suse.de>
To: christoph <christoph@scalex86.org>
Cc: ak@suse.de, linux-kernel@vger.kernel.org, shai@scalex86.org
Subject: Re: [PATCH] Move some variables into the "most_readonly" section??
Date: Wed, 8 Jun 2005 15:18:39 +0200 [thread overview]
Message-ID: <20050608131839.GP23831@wotan.suse.de> (raw)
In-Reply-To: <Pine.LNX.4.62.0506071253020.2850@ScMPusgw>
On Tue, Jun 07, 2005 at 12:58:38PM -0700, christoph wrote:
> These variables cause false sharing in some circumstances. However, they
> are just small pointers and 4 byte ints. So this patch would result in
> some wastage of memory since each of those pointers then would occupy a
> whole cache line.
>
> Do we have any provisions for this situation? Or do we need a new section
> for mostly_readonly?
You lost me - when the variable is in the mostly readonly section then
there should not be any false sharing because all the data on these
cache lines should be always in SHARED state. And there is no wasted
memory because the variables can be packed tightly there.
However this means __cacheline_aligned_mostly_readonly doesnt make much
sense since there is no need for alignment in read only. How about
replacing it with a __mostly_readonly that doesnt align and remove
__cacheline_aligned_mostly_readonly?
-Andi
next prev parent reply other threads:[~2005-06-08 13:18 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-07 19:58 christoph
2005-06-08 13:18 ` Andi Kleen [this message]
2005-06-14 22:54 ` christoph
2005-06-14 23:04 ` Andi Kleen
2005-06-14 23:17 ` Christoph Lameter
2005-06-14 23:19 ` Andi Kleen
2005-06-14 23:27 ` Christoph Lameter
2005-06-14 23:54 ` Andi Kleen
2005-06-14 23:23 ` Andrew Morton
2005-06-14 23:46 ` christoph
2005-06-14 23:58 ` Andrew Morton
2005-06-15 0:05 ` christoph
2005-06-15 0:16 ` Andrew Morton
2005-06-15 0:41 ` Andi Kleen
2005-06-17 13:55 ` Anton Blanchard
2005-06-27 23:17 ` christoph
2005-06-15 0:18 ` Nick Piggin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20050608131839.GP23831@wotan.suse.de \
--to=ak@suse.de \
--cc=christoph@scalex86.org \
--cc=linux-kernel@vger.kernel.org \
--cc=shai@scalex86.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®