From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Simon Martin <smartin@milliways.cl>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: VCPUOP_set_periodic_timer
Date: Thu, 14 Nov 2013 21:39:21 +0000 [thread overview]
Message-ID: <52854309.7000504@citrix.com> (raw)
In-Reply-To: <em4158cadd-9eab-4a26-80ba-b3a3b311bee2@smartin-alien>
[-- Attachment #1.1: Type: text/plain, Size: 853 bytes --]
On 14/11/2013 21:18, Simon Martin wrote:
> Hi all,
>
> I need a periodic timer running at ideally at 125 microseconds and at
> least 500 microseconds. I've just found the VCPUOP_set_periodic_timer,
> however there is a comment saying "periods less than one millisecond
> may not be supported".
>
> I will be running on an x64 machine. Is this supported? If not, is
> there any alternate means of generating a fast interrupt?
>
> Regards.
What is the usecase here? 125us is very short indeed. Xen certainly
cant guarantee anything more accurate than 50us. Unless the affected
vcpu is running uncontested on the hardware, there is very little chance
that the vcpu will indeed be woken up again in 125us.
It sounds as if you are looking for some pseudo realtime system, at
which point you might want to consider a different scheduler.
~Andrew
[-- Attachment #1.2: Type: text/html, Size: 2081 bytes --]
[-- Attachment #2: Type: text/plain, Size: 126 bytes --]
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2013-11-14 21:39 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-14 21:18 VCPUOP_set_periodic_timer Simon Martin
2013-11-14 21:39 ` Andrew Cooper [this message]
2013-11-15 11:24 ` VCPUOP_set_periodic_timer Simon Martin
2013-11-15 11:36 ` VCPUOP_set_periodic_timer Keir Fraser
2013-11-15 11:45 ` VCPUOP_set_periodic_timer Simon Martin
2013-11-15 11:56 ` VCPUOP_set_periodic_timer Keir Fraser
2013-11-15 12:37 ` VCPUOP_set_periodic_timer Simon Martin
2013-11-15 13:10 ` VCPUOP_set_periodic_timer Keir Fraser
2013-11-15 13:13 ` VCPUOP_set_periodic_timer Andrew Cooper
2013-11-15 13:39 ` VCPUOP_set_periodic_timer Keir Fraser
2013-11-15 11:41 ` VCPUOP_set_periodic_timer Andrew Cooper
2013-11-15 12:02 ` VCPUOP_set_periodic_timer Simon Martin
2013-11-15 12:17 ` VCPUOP_set_periodic_timer Andrew Cooper
2013-11-15 12:46 ` VCPUOP_set_periodic_timer Nate Studer
2013-11-15 12:52 ` VCPUOP_set_periodic_timer Andrew Cooper
2013-11-15 12:54 ` VCPUOP_set_periodic_timer George Dunlap
2013-11-15 21:10 ` VCPUOP_set_periodic_timer Dario Faggioli
2013-11-16 20:37 ` VCPUOP_set_periodic_timer Simon Martin
2013-11-18 18:28 ` VCPUOP_set_periodic_timer Dario Faggioli
2013-11-26 14:50 ` PV guest timings Simon Martin
2013-11-26 15:11 ` Keir Fraser
2013-11-26 15:38 ` Simon Martin
2013-11-26 23:33 ` Dario Faggioli
2013-11-27 2:32 ` Simon Martin
2013-11-27 8:46 ` Dario Faggioli
2013-11-27 12:04 ` Simon Martin
2013-11-27 10:38 ` David Vrabel
2013-11-27 14:07 ` Simon Martin
2013-11-26 23:31 ` Dario Faggioli
2013-11-27 2:36 ` Simon Martin
2013-11-27 8:56 ` Dario Faggioli
2013-11-27 13:00 ` Simon Martin
2013-11-28 11:16 ` Dario Faggioli
2013-11-28 11:57 ` Simon Martin
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=52854309.7000504@citrix.com \
--to=andrew.cooper3@citrix.com \
--cc=smartin@milliways.cl \
--cc=xen-devel@lists.xen.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).