From: Andi Kleen <ak@suse.de>
To: Benjamin LaHaise <bcrl@linux.intel.com>
Cc: Andrew Morton <akpm@osdl.org>,
linux-mm@kvack.org, netdev@vger.kernel.org
Subject: Re: [PATCH] avoid atomic op on page free
Date: Tue, 7 Mar 2006 07:30:27 +0100 [thread overview]
Message-ID: <200603070730.27999.ak@suse.de> (raw)
In-Reply-To: <20060307015229.GJ32565@linux.intel.com>
On Tuesday 07 March 2006 02:52, Benjamin LaHaise wrote:
> Those 1-2 cycles are free if you look at how things get scheduled with the
> execution of the surrounding code. I bet $20 that you can't find a modern
> CPU where the cost is measurable (meaning something like a P4, Athlon).
> If this level of cost for the common case is a concern, it's probably worth
> making atomic_dec_and_test() inline for page_cache_release(). The overhead
> of the function call and the PageCompound() test is probably more than what
> we're talking about as you're increasing the cache footprint and actually
> performing a write to memory.
The test should be essentially free at least on an out of order CPU. Not quite sure
about in order though.
-Andi
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2006-03-07 6:30 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-07 0:10 [PATCH] avoid atomic op on page free Benjamin LaHaise
2006-03-07 0:50 ` Andrew Morton
2006-03-07 1:11 ` Benjamin LaHaise
2006-03-07 1:39 ` Andrew Morton
2006-03-07 1:52 ` Benjamin LaHaise
2006-03-07 6:30 ` Andi Kleen [this message]
2006-03-07 2:04 ` Nick Piggin
2006-03-07 2:10 ` Benjamin LaHaise
2006-03-07 4:08 ` Nick Piggin
2006-03-07 2:30 ` Chen, Kenneth W
2006-03-07 4:13 ` Nick Piggin
2006-03-07 1:21 ` Rick Jones
2006-03-07 1:53 ` Nick Piggin
2006-03-07 1:58 ` Benjamin LaHaise
2006-03-07 2:14 ` 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=200603070730.27999.ak@suse.de \
--to=ak@suse.de \
--cc=akpm@osdl.org \
--cc=bcrl@linux.intel.com \
--cc=linux-mm@kvack.org \
--cc=netdev@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.