From: "Andi Kleen" <andi@firstfloor.org>
To: miaox@cn.fujitsu.com
Cc: "Andi Kleen" <andi@firstfloor.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Theodore Ts'o" <tytso@mit.edu>,
"Linux Kernel" <linux-kernel@vger.kernel.org>,
"Linux Ext4" <linux-ext4@vger.kernel.org>,
"Linux Btrfs" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH V2 1/3] lib: introduce some memory copy macros and functions
Date: Wed, 8 Sep 2010 14:19:25 +0200 (CEST) [thread overview]
Message-ID: <46238.91.60.152.217.1283948365.squirrel@www.firstfloor.org> (raw)
> According to the data, the length of the most copies is >=128.
Thanks for the data. Large is easier to optimize than small, that's good.
Could you also measure how many memsets need the backwards copy?
(should be easy to add)
If the number is small that needs backwards then the easiest fix
would be to simply call the normal memcpy in the forward case.
That is for backward could also use a string instruction copy
of course, just have to set the direction flag.
That would be a very small code change.
-Andi
WARNING: multiple messages have this Message-ID (diff)
From: "Andi Kleen" <andi@firstfloor.org>
To: miaox@cn.fujitsu.com
Cc: "Andi Kleen" <andi@firstfloor.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Theodore Ts'o" <tytso@mit.edu>,
"Linux Kernel" <linux-kernel@vger.kernel.org>,
"Linux Ext4" <linux-ext4@vger.kernel.org>,
"Linux Btrfs" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH V2 1/3] lib: introduce some memory copy macros and functions
Date: Wed, 8 Sep 2010 14:19:25 +0200 (CEST) [thread overview]
Message-ID: <46238.91.60.152.217.1283948365.squirrel@www.firstfloor.org> (raw)
> According to the data, the length of the most copies is >=128.
Thanks for the data. Large is easier to optimize than small, that's good.
Could you also measure how many memsets need the backwards copy?
(should be easy to add)
If the number is small that needs backwards then the easiest fix
would be to simply call the normal memcpy in the forward case.
That is for backward could also use a string instruction copy
of course, just have to set the direction flag.
That would be a very small code change.
-Andi
next reply other threads:[~2010-09-08 12:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-08 12:19 Andi Kleen [this message]
2010-09-08 12:19 ` [PATCH V2 1/3] lib: introduce some memory copy macros and functions Andi Kleen
2010-09-08 12:57 ` Miao Xie
2010-09-08 13:05 ` Andi Kleen
2010-09-08 13:32 ` Miao Xie
-- strict thread matches above, loose matches on Subject: below --
2010-09-02 5:46 Miao Xie
2010-09-02 5:46 ` Miao Xie
2010-09-02 8:55 ` Andi Kleen
2010-09-02 10:11 ` Miao Xie
2010-09-02 10:40 ` Andi Kleen
2010-09-08 11:05 ` Miao Xie
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=46238.91.60.152.217.1283948365.squirrel@www.firstfloor.org \
--to=andi@firstfloor.org \
--cc=akpm@linux-foundation.org \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=miaox@cn.fujitsu.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tytso@mit.edu \
/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.