From: Ingo Molnar <mingo@elte.hu>
To: Zachary Amsden <zach@vmware.com>
Cc: Glauber de Oliveira Costa <gcosta@redhat.com>,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
rusty@rustcorp.com.au, jeremy@goop.org, --cc@redhat.com,
avi@quramnet.com, kvm-devel@lists.sourceforge.net,
Glauber de Oliveira Costa <glauber@t60.localdomain>,
Dan Hecht <dhecht@vmware.com>, Garrett Smith <garrett@vmware.com>
Subject: Re: [PATCH] raise tsc clocksource rating
Date: Tue, 30 Oct 2007 00:02:13 +0100 [thread overview]
Message-ID: <20071029230213.GA1982@elte.hu> (raw)
In-Reply-To: <1193698505.9793.90.camel@bodhitayantram.eng.vmware.com>
* Zachary Amsden <zach@vmware.com> wrote:
> On Mon, 2007-10-29 at 23:48 +0100, Ingo Molnar wrote:
> > * Zachary Amsden <zach@vmware.com> wrote:
>
> > if it's inaccurate why are you exposing it to the guest then? Native
> > only uses the TSC if it's safe and accurate to do so.
>
> Not every guest support paravirt, but for correctness, all guests
> require TSC, which must be exposed all the way up to userspace, no
> matter what the efficiency or accuracy may be.
but if there's a perfect TSC available (there is such hardware) then the
TSC _is_ the best clocksource. Paravirt now turns it off unconditionally
in essence.
anyway, that's at most an optimization issue. No strong feelings here,
and we can certainly delay this patch until this gets all sorted out.
Ingo
next prev parent reply other threads:[~2007-10-29 23:02 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-29 23:10 [PATCH] raise tsc clocksource rating Glauber de Oliveira Costa
[not found] ` <11936994092607-git-send-email-gcosta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2007-10-29 22:17 ` Thomas Gleixner
2007-10-29 22:36 ` Ingo Molnar
2007-10-30 1:26 ` john stultz
[not found] ` <alpine.LFD.0.9999.0710292315280.3186-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-10-30 2:39 ` Rusty Russell
[not found] ` <200710301339.23628.rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
2007-10-30 7:37 ` Ingo Molnar
[not found] ` <20071030073736.GA21843-X9Un+BFzKDI@public.gmane.org>
2007-10-30 10:52 ` Rusty Russell
2007-10-30 12:13 ` Glauber de Oliveira Costa
2007-10-29 22:42 ` Zachary Amsden
[not found] ` <1193697734.9793.86.camel-cxY/u30q8FloTgUnLF1by8fTvwmfpRNyZeezCHUQhQ4@public.gmane.org>
2007-10-29 22:45 ` Jeremy Fitzhardinge
2007-10-29 22:48 ` Ingo Molnar
[not found] ` <20071029224852.GA27547-X9Un+BFzKDI@public.gmane.org>
2007-10-29 22:52 ` Jeremy Fitzhardinge
2007-10-29 22:55 ` Ingo Molnar
[not found] ` <20071029225528.GA31293-X9Un+BFzKDI@public.gmane.org>
2007-10-29 23:17 ` Jeremy Fitzhardinge
[not found] ` <47266A00.4040408-TSDbQ3PG+2Y@public.gmane.org>
2007-10-29 23:21 ` Ingo Molnar
[not found] ` <20071029232140.GA10518-X9Un+BFzKDI@public.gmane.org>
2007-10-29 23:33 ` Jeremy Fitzhardinge
2007-10-30 0:45 ` Ian Pratt
[not found] ` <8A87A9A84C201449A0C56B728ACF491E34C5F5-sZfJFUT1i4lUWNNKjvdVWtlxNDNUtst69dF7HbQ/qKg@public.gmane.org>
2007-10-30 7:19 ` Ingo Molnar
2007-10-29 22:55 ` Zachary Amsden
2007-10-29 23:02 ` Ingo Molnar [this message]
2007-10-29 23:13 ` Zachary Amsden
[not found] ` <1193699638.9793.97.camel-cxY/u30q8FloTgUnLF1by8fTvwmfpRNyZeezCHUQhQ4@public.gmane.org>
2007-10-29 23:17 ` Ingo Molnar
2007-10-30 12:02 ` Glauber de Oliveira Costa
[not found] ` <47271D4A.8030707-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2007-10-30 17:58 ` Zachary Amsden
[not found] ` <20071029230213.GA1982-X9Un+BFzKDI@public.gmane.org>
2007-10-29 23:24 ` Dan Hecht
[not found] ` <47266B90.8000008-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
2007-10-30 4:24 ` Avi Kivity
2007-10-30 7:14 ` Ingo Molnar
[not found] ` <1193698505.9793.90.camel-cxY/u30q8FloTgUnLF1by8fTvwmfpRNyZeezCHUQhQ4@public.gmane.org>
2007-10-30 11:59 ` Glauber de Oliveira Costa
2007-10-30 0:17 ` H. Peter Anvin
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=20071029230213.GA1982@elte.hu \
--to=mingo@elte.hu \
--cc=--cc@redhat.com \
--cc=avi@quramnet.com \
--cc=dhecht@vmware.com \
--cc=garrett@vmware.com \
--cc=gcosta@redhat.com \
--cc=glauber@t60.localdomain \
--cc=jeremy@goop.org \
--cc=kvm-devel@lists.sourceforge.net \
--cc=linux-kernel@vger.kernel.org \
--cc=rusty@rustcorp.com.au \
--cc=tglx@linutronix.de \
--cc=zach@vmware.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