From: Gleb Natapov <gleb@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Beth Kon <eak@us.ibm.com>,
dlaor@redhat.com, Sheng Yang <sheng@linux.intel.com>,
kvm@vger.kernel.org
Subject: Re: The HPET issue on Linux
Date: Wed, 6 Jan 2010 21:44:11 +0200 [thread overview]
Message-ID: <20100106194411.GA24476@redhat.com> (raw)
In-Reply-To: <4B44E330.4080805@codemonkey.ws>
On Wed, Jan 06, 2010 at 01:23:28PM -0600, Anthony Liguori wrote:
> On 01/06/2010 01:20 PM, Beth Kon wrote:
> >Beth Kon wrote:
> >>I will try to look into this. Since HPET is edge-triggered,
> >>looks like this problem is of a different nature than PIT. Is
> >>this a solid failure or intermittent?
> >Anthony just explained that on x86, even edge-triggered interrupts
> >are queued in the apic and an eoi will occur, so this is not
> >different than the PIT.
>
> Not quite queued in the sense that multiple events will be delivered
> in order, but I think the point is that you can still detect whether
> delivery succeeded by counting APIC EOIs.
>
> The trouble is that historically we've struggled with doing this in
> userspace. Maybe it's time to revisit.
>
We reinject PIT interrupts from kernel and RTC interrupts from
userspace.
--
Gleb.
next prev parent reply other threads:[~2010-01-06 19:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-06 9:48 The HPET issue on Linux Sheng Yang
2010-01-06 10:09 ` Gleb Natapov
2010-01-06 10:23 ` Dor Laor
2010-01-06 18:36 ` Beth Kon
2010-01-06 19:20 ` Beth Kon
2010-01-06 19:23 ` Anthony Liguori
2010-01-06 19:44 ` Gleb Natapov [this message]
2010-01-06 19:51 ` Anthony Liguori
2010-01-06 20:37 ` Gleb Natapov
2010-01-06 22:42 ` Anthony Liguori
2010-01-07 6:45 ` Gleb Natapov
2010-01-07 3:01 ` Sheng Yang
2010-02-02 18:13 ` No longer working on HPET Beth Kon
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=20100106194411.GA24476@redhat.com \
--to=gleb@redhat.com \
--cc=anthony@codemonkey.ws \
--cc=dlaor@redhat.com \
--cc=eak@us.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=sheng@linux.intel.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;
as well as URLs for NNTP newsgroup(s).