From: Steffen Liebergeld <usenet@gmx.eu>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] branches are expensive
Date: Tue, 17 Mar 2009 11:05:24 +0000 (UTC) [thread overview]
Message-ID: <gpo05k$6u4$1@ger.gmane.org> (raw)
Hi,
while measuring the execution of an ARM guest, I encountered that branches are
extremely expensive in terms of executed host instructions. A single ARM
branch takes 148 to 152 host instructions. In my setup host and guest use the
ARM instruction set architecture.
My question is what makes branches so expensive? What code is run when
executing a branch? Other instructions are translated to 14 to 40
instructions.
Any help is appreciated.
Greetings, Steffen
next reply other threads:[~2009-03-17 11:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-17 11:05 Steffen Liebergeld [this message]
2009-03-17 11:18 ` [Qemu-devel] branches are expensive Avi Kivity
2009-03-17 11:32 ` [Qemu-devel] " Jan Kiszka
2009-03-17 12:31 ` Steffen Liebergeld
2009-03-17 12:51 ` Paul Brook
2009-03-17 13:24 ` Avi Kivity
2009-03-19 10:07 ` Steffen Liebergeld
2009-03-19 10:30 ` Laurent Desnogues
2009-03-19 10:39 ` Steffen Liebergeld
2009-03-19 11:06 ` Laurent Desnogues
2009-03-19 10:52 ` Avi Kivity
2009-03-19 11:34 ` Paul Brook
2009-03-17 11:36 ` Steffen Liebergeld
2009-03-17 13:30 ` [Qemu-devel] " Laurent Desnogues
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='gpo05k$6u4$1@ger.gmane.org' \
--to=usenet@gmx.eu \
--cc=qemu-devel@nongnu.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;
as well as URLs for NNTP newsgroup(s).