From: "H. Peter Anvin" <hpa@zytor.com>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Ulrich Drepper <drepper@redhat.com>,
Davide Libenzi <davidel@xmailserver.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andi Kleen <ak@suse.de>
Subject: Re: getting processor numbers
Date: Tue, 03 Apr 2007 22:16:37 -0700 [thread overview]
Message-ID: <461334B5.7070607@zytor.com> (raw)
In-Reply-To: <4613330C.1020701@cosmosbay.com>
Eric Dumazet wrote:
>
> There is one thing that always worried me.
>
> Intel & AMD manuals make clear that mixing data and program in the same
> page is bad for performance.
>
> In particular, x86_64 vsyscall put jiffies and other
> vsyscall_gtod_data_t right in the midle of code. That is certainly not
> wise.
>
> A probably sane implementation should use two pages, one for code, one
> for data.
>
Mutable data should be separated from code. I think any current CPU
will do fine as long as they are in separate 128-byte chunks, but they
need at least that much separation.
Readonly data does not need to be separated from code.
-hpa
next prev parent reply other threads:[~2007-04-04 5:18 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-03 16:54 getting processor numbers Ulrich Drepper
2007-04-03 17:30 ` linux-os (Dick Johnson)
2007-04-03 17:37 ` Ulrich Drepper
2007-04-03 17:56 ` Dr. David Alan Gilbert
2007-04-03 18:11 ` Andi Kleen
2007-04-03 17:17 ` Ulrich Drepper
2007-04-03 17:22 ` Alan Cox
2007-04-03 17:30 ` Andi Kleen
2007-04-03 20:24 ` Jeremy Fitzhardinge
2007-04-03 17:27 ` Andi Kleen
2007-04-03 17:30 ` Ulrich Drepper
2007-04-03 17:35 ` Andi Kleen
2007-04-03 17:45 ` Ulrich Drepper
2007-04-03 17:58 ` Andi Kleen
2007-04-03 18:05 ` Ulrich Drepper
2007-04-03 18:11 ` Andi Kleen
2007-04-03 18:21 ` Ulrich Drepper
2007-04-03 17:44 ` Siddha, Suresh B
2007-04-03 17:59 ` Ulrich Drepper
2007-04-03 19:40 ` Jakub Jelinek
2007-04-03 20:13 ` Ingo Oeser
2007-04-03 23:38 ` J.A. Magallón
2007-04-03 19:55 ` Ulrich Drepper
2007-04-03 20:13 ` Siddha, Suresh B
2007-04-03 20:19 ` Ulrich Drepper
2007-04-03 20:32 ` Eric Dumazet
2007-04-03 20:20 ` Nathan Lynch
2007-04-03 19:15 ` Davide Libenzi
2007-04-03 19:32 ` Ulrich Drepper
2007-04-04 0:31 ` H. Peter Anvin
2007-04-04 0:35 ` Jeremy Fitzhardinge
2007-04-04 0:38 ` H. Peter Anvin
2007-04-04 5:09 ` Eric Dumazet
2007-04-04 5:16 ` H. Peter Anvin [this message]
2007-04-04 5:22 ` Jeremy Fitzhardinge
2007-04-04 5:40 ` H. Peter Anvin
2007-04-04 5:46 ` Eric Dumazet
2007-04-04 5:29 ` Eric Dumazet
2007-04-03 20:16 ` Andrew Morton
[not found] ` <4612BB89.8040102@redhat.com>
[not found] ` <20070403141348.9bcdb13e.akpm@linux-foundation.org>
2007-04-03 22:13 ` Ulrich Drepper
2007-04-03 22:48 ` Andrew Morton
2007-04-03 23:00 ` Ulrich Drepper
2007-04-03 23:23 ` Andrew Morton
2007-04-03 23:54 ` Ulrich Drepper
2007-04-04 2:55 ` Paul Jackson
2007-04-04 8:39 ` Oleg Nesterov
2007-04-04 9:39 ` Ingo Molnar
2007-04-04 8:57 ` Oleg Nesterov
2007-04-04 10:01 ` Ingo Molnar
2007-04-04 2:58 ` Paul Jackson
2007-04-04 3:04 ` Paul Jackson
2007-04-04 2:52 ` Paul Jackson
2007-04-04 2:04 ` Paul Jackson
2007-04-04 6:47 ` Jakub Jelinek
2007-04-04 7:02 ` Paul Jackson
2007-04-04 14:51 ` Cliff Wickman
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=461334B5.7070607@zytor.com \
--to=hpa@zytor.com \
--cc=ak@suse.de \
--cc=akpm@linux-foundation.org \
--cc=dada1@cosmosbay.com \
--cc=davidel@xmailserver.org \
--cc=drepper@redhat.com \
--cc=jeremy@goop.org \
--cc=linux-kernel@vger.kernel.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.