From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: <ak@suse.de>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>
Subject: RE: [patch] speed up single bio_vec allocation
Date: Thu, 7 Dec 2006 20:23:07 -0800 [thread overview]
Message-ID: <000001c71a80$90342120$f180030a@amr.corp.intel.com> (raw)
In-Reply-To: <p733b7rdsut.fsf@bingen.suse.de>
Andi Kleen wrote on Thursday, December 07, 2006 6:28 PM
> "Chen, Kenneth W" <kenneth.w.chen@intel.com> writes:
> > I tried to use cache_line_size() to find out the alignment of struct bio, but
> > stumbled on that it is a runtime function for x86_64.
>
> It's a single global variable access:
>
> #define cache_line_size() (boot_cpu_data.x86_cache_alignment)
>
> Or do you mean it caused cache misses? boot_cpu_data is cache aligned
> and practically read only, so there shouldn't be any false sharing at least.
No, I was looking for a generic constant that describes cache line size.
I needed a constant in order to avoid runtime check and to rely on compiler
to optimize a conditional check away.
next prev parent reply other threads:[~2006-12-08 4:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-04 19:27 Chen, Kenneth W
2006-12-04 20:06 ` Jens Axboe
2006-12-04 20:36 ` Chen, Kenneth W
2006-12-04 20:43 ` Jens Axboe
2006-12-06 10:08 ` Jens Axboe
2006-12-06 10:56 ` Jens Axboe
2006-12-06 18:19 ` Chen, Kenneth W
2006-12-07 19:22 ` Nate Diller
2006-12-07 19:36 ` Chen, Kenneth W
2006-12-07 21:46 ` Nate Diller
2006-12-07 21:52 ` Chen, Kenneth W
2006-12-07 22:33 ` Nate Diller
2006-12-08 8:01 ` Jens Axboe
2006-12-08 2:27 ` Andi Kleen
2006-12-08 4:23 ` Chen, Kenneth W [this message]
2006-12-08 4:37 ` Andi Kleen
2006-12-08 22:14 Chen, Kenneth W
2006-12-14 20:23 ` Jens Axboe
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='000001c71a80$90342120$f180030a@amr.corp.intel.com' \
--to=kenneth.w.chen@intel.com \
--cc=ak@suse.de \
--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 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®