From: Zou Nan hai <nanhai.zou@intel.com>
To: linux-kernel@vger.kernel.org
Subject: possible performance issue in 4-level page tables
Date: 01 Feb 2005 12:19:30 +0800 [thread overview]
Message-ID: <1107231570.2555.19.camel@linux-znh> (raw)
There is a performance regression of lmbench
lat_proc fork result on ia64.
in
2.6.10
I got
Process fork+exit:164.8438 microseconds.
in 2.6.11-rc2
Process fork+exit:183.8621 microseconds.
I believe this regression was caused by
the 4-level page tables change.
Since most of the kernel time spend in lat_proc fork is copy_page_range
in fork path and clear_page_range in the exit path. Now they are 1 level
deeper.
Though pud and pgd is same on IA64, there is still some overhead
introduced I think.
Are any other architectures seeing the same sort of results?
Zou Nan hai
next reply other threads:[~2005-02-01 5:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-01 4:19 Zou Nan hai [this message]
2005-02-01 7:46 ` possible performance issue in 4-level page tables 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=1107231570.2555.19.camel@linux-znh \
--to=nanhai.zou@intel.com \
--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