From: Keir Fraser <keir@xensource.com>
To: "Zulauf, John" <john.zulauf@intel.com>,
Mats Petersson <mats@planetcatfish.com>,
Trolle Selander <trolle.selander@gmail.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: Buffered IO for IO?
Date: Tue, 24 Jul 2007 07:31:52 +0100 [thread overview]
Message-ID: <C2CB5B68.B48D%keir@xensource.com> (raw)
In-Reply-To: <BD262A443AD428499D90AF8368C4528D8A18BE@fmsmsx411.amr.corp.intel.com>
On 23/7/07 20:38, "Zulauf, John" <john.zulauf@intel.com> wrote:
> I'm running on an 8-core system with currently only two HVM domains
> (with currently single VCPU each). Both top on Dom0 and xm top, don't
> seem to indicate qemu-dm as the performance bottleneck. However, I'm
> not sure about roundtrip latency through the xenstore to qemu and back.
Well, maybe you are just seeing VMEXIT time then. You might try adding some
RDTSC from when a notification is sent to qemu until when your HVM vcpu is
rewoken, and see what the latency looks like. It shouldn't be all that bad
if dom0 is on another cpu and is otherwise fairly idle.
Also, you could see how many characters are sent and received to start a
windbg session. If there are a surprisingly large number of bytes received
then it may be the receive direction is causing more trouble than the
transmit direction.
-- Keir
prev parent reply other threads:[~2007-07-24 6:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-19 11:53 special video mode numbers Jan Beulich
2007-07-20 21:33 ` Buffered IO for IO? Zulauf, John
2007-07-21 9:44 ` Keir Fraser
2007-07-21 9:50 ` Mats Petersson
2007-07-21 10:59 ` Trolle Selander
2007-07-21 11:08 ` Keir Fraser
2007-07-23 18:49 ` Zulauf, John
[not found] ` <BD262A443AD428499D90AF8368C4528D8A189E@fmsmsx411.amr.corp. intel.com>
2007-07-23 19:00 ` Mats Petersson
2007-07-23 19:38 ` Zulauf, John
[not found] ` <BD262A443AD428499D90AF8368C4528D8A18BE@fmsmsx411.amr.corp. intel.com>
2007-07-23 20:07 ` Mats Petersson
2007-07-24 6:31 ` Keir Fraser [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=C2CB5B68.B48D%keir@xensource.com \
--to=keir@xensource.com \
--cc=john.zulauf@intel.com \
--cc=mats@planetcatfish.com \
--cc=trolle.selander@gmail.com \
--cc=xen-devel@lists.xensource.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 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.