From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: kurt.hackel@oracle.com,
"Xen-Devel (E-mail)" <xen-devel@lists.xensource.com>,
Keir Fraser <keir.fraser@eu.citrix.com>,
Jan Beulich <JBeulich@novell.com>
Subject: Re: rdtscP and xen (and maybe the app-tsc answer I've been looking for)
Date: Tue, 22 Sep 2009 12:52:41 -0700 [thread overview]
Message-ID: <4AB92B09.8020308@goop.org> (raw)
In-Reply-To: <60339ddd-4a9d-4efe-bd0a-bcc09bc6d468@default>
On 09/22/09 12:36, Dan Magenheimer wrote:
> Are you (Jeremy) still assuming that rdtsc/rdtscp are NOT
> emulated? Or are you trying to define a vsyscall+pvclock
> mechanism for the same constrained environments
> so that HFTSAs have a choice of using clock_gettime
> instead of pvrdtsc, either of which will be fast?
>
Yes, I'm assuming they're not emulated. If you're emulating them
there's no reason to add any extra complexity to usermode by adding any
other ABI: rdtsc can be rdtsc and rdtscp can be rdtscp with no
Xen/ABI-imposed constraints on TSC_AUX.
Once you're talking about layering another ABI onto the tsc, then
there's no need to consider emulation because you can do all the
necessary correction to get a canonical timestamp without it.
J
next prev parent reply other threads:[~2009-09-22 19:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-18 16:30 rdtscP and xen (and maybe the app-tsc answer I've been looking for) Dan Magenheimer
2009-09-18 20:27 ` Dan Magenheimer
2009-09-18 22:55 ` Jeremy Fitzhardinge
2009-09-19 15:34 ` Dan Magenheimer
2009-09-21 14:47 ` Dan Magenheimer
2009-09-21 18:36 ` Jeremy Fitzhardinge
2009-09-21 22:20 ` Dan Magenheimer
2009-09-21 22:50 ` Jeremy Fitzhardinge
2009-09-21 23:29 ` Dan Magenheimer
2009-09-21 23:55 ` Jeremy Fitzhardinge
2009-09-22 0:11 ` Dan Magenheimer
2009-09-22 0:42 ` Jeremy Fitzhardinge
2009-09-22 19:36 ` Dan Magenheimer
2009-09-22 19:52 ` Jeremy Fitzhardinge [this message]
2009-09-22 20:22 ` Dan Magenheimer
2009-09-22 22:18 ` Jeremy Fitzhardinge
2009-09-22 7:44 ` Jan Beulich
2009-09-22 15:00 ` Dan Magenheimer
2009-09-22 15:16 ` Jan Beulich
2009-09-22 17:15 ` Jeremy Fitzhardinge
2009-09-22 7:39 ` Jan Beulich
2009-09-22 17:26 ` Jeremy Fitzhardinge
2009-09-21 8:17 ` Jan Beulich
2009-09-21 14:04 ` Dan Magenheimer
2009-09-21 14:18 ` Jan Beulich
2009-09-21 15:25 ` Dan Magenheimer
2009-09-21 15:41 ` Keir Fraser
2009-09-21 15:53 ` Keir Fraser
2009-09-21 16:55 ` Dan Magenheimer
2009-09-21 17:02 ` Keir Fraser
2009-09-21 17:56 ` Dan Magenheimer
2009-09-21 18:17 ` Keir Fraser
2009-09-21 21:47 ` Dan Magenheimer
2009-09-21 16:03 ` Jan Beulich
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=4AB92B09.8020308@goop.org \
--to=jeremy@goop.org \
--cc=JBeulich@novell.com \
--cc=dan.magenheimer@oracle.com \
--cc=keir.fraser@eu.citrix.com \
--cc=kurt.hackel@oracle.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.