From: Andi Kleen <ak@suse.de>
To: Christoph Lameter <clameter@sgi.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: Re: Some interesting observations when trying to optimize vmstat handling
Date: Fri, 9 Nov 2007 00:07:42 +0100 [thread overview]
Message-ID: <200711090007.43424.ak@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.64.0711081141180.9694@schroedinger.engr.sgi.com>
> There is an interrupt enable overhead of 48 cycles that would be good to
> be able to eliminate (Kernel code usually moves counter increments into
> a neighboring interrupt disable section so that __ function can be used).
Replace the push flags ; popf with test $IFMASK,flags ; jz 1f; sti ; 1:
That will likely make it much faster (but also bigger)
The only problem is that there might be some code who relies on
restore_flags() restoring other flags that IF, but at least for interrupts
and local_irq_save/restore it should be fine to change.
-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:[~2007-11-08 23:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-08 19:58 Christoph Lameter
2007-11-08 23:07 ` Andi Kleen [this message]
2007-11-08 23:25 ` Christoph Lameter
2007-11-09 0:19 ` Jeremy Fitzhardinge
2007-11-09 15:56 ` Andi Kleen
2007-11-08 23:24 ` David Miller, Christoph Lameter
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=200711090007.43424.ak@suse.de \
--to=ak@suse.de \
--cc=clameter@sgi.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mathieu.desnoyers@polymtl.ca \
/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