linux-um archives
 help / color / mirror / Atom feed
From: Jeff Dike <jdike@addtoit.com>
To: George Washington Dunlap III <dunlapg@umich.edu>
Cc: William Stearns <wstearns@pobox.com>,
	ML-uml-devel <user-mode-linux-devel@lists.sourceforge.net>
Subject: Re: [uml-devel] Overhead of UML-skas
Date: Mon, 01 Mar 2004 21:51:22 -0500	[thread overview]
Message-ID: <200403020251.i222pMM9026039@ccure.user-mode-linux.org> (raw)
In-Reply-To: Your message of "Mon, 01 Mar 2004 19:55:16 EST." <Pine.LNX.4.44.0403011920310.23055-100000@stclair.eecs.umich.edu>

dunlapg@umich.edu said:
> Our standard mode of operation is to have ayncronous I/O turned off by
> default, because of the extra process that's created.  

Have the build on the host do it on a O_SYNC filesystem and see how fast it
goes.

> (It has to do
> with the research we're doing right now.)  I explicitly enabled it for
> this build, and verified that the helper process was being created. It
> resulted in a marked speed increase (about 6% for this benchmark, if
> you're interested). 

FWIW, I'd expect a 20-30% slowdown from the host on a kernel build.  I see
25-30% on my laptop, Matt Ayes in #uml said he saw 20% on one of his servers.

				Jeff



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

      reply	other threads:[~2004-03-02  2:33 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-03-01 23:48 [uml-devel] Overhead of UML-skas George Washington Dunlap III
2004-03-02  0:13 ` William Stearns
2004-03-02  0:55   ` George Washington Dunlap III
2004-03-02  2:51     ` Jeff Dike [this message]

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=200403020251.i222pMM9026039@ccure.user-mode-linux.org \
    --to=jdike@addtoit.com \
    --cc=dunlapg@umich.edu \
    --cc=user-mode-linux-devel@lists.sourceforge.net \
    --cc=wstearns@pobox.com \
    /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