From: "Karl Reichert" <Karl-Trampe@domain.hid>
To: "M. Koehrer" <mathias_koehrer@domain.hid>, xenomai@xenomai.org
Subject: Re: [Xenomai-help] TSCs synchron on multi-core CPUs?
Date: Tue, 03 Jun 2008 16:29:47 +0200 [thread overview]
Message-ID: <20080603142947.115490@domain.hid> (raw)
In-Reply-To: <18504269.1212502025901.JavaMail.ngmail@domain.hid>
> Hi everybody,
>
> I have a question concerning the time stamp counters of the Intel
> core2duo/quad CPUs.
> They will be used e.g. with the Xenomai native skin call rt_time_tsc which
> ends up in
> an assembler statement "rdtsc".
> My question is now:
> Are the values of TSC synchron with dual/quad core CPUs? Or is there a
> possible drift between
> the CPUs?
> Background of the question is:
> I want to measure the time of a event that occurs within one task.
> A second event is checked in another task on a different core. The time
> difference between the
> events has to be checked.
> Can this be done precisely with rdtsc() or is a mechanism required that
> uses the TSC of exactly one
> core?
>
> Thanks for all hints on that question!
>
> Regards
>
> Mathias
Hi Mathias,
TSC of the cores may differ: http://en.wikipedia.org/wiki/Time_Stamp_Counter
Best regards
Karl
--
von Karl Reichert
next prev parent reply other threads:[~2008-06-03 14:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-03 14:07 [Xenomai-help] TSCs synchron on multi-core CPUs? M. Koehrer
2008-06-03 14:29 ` Karl Reichert [this message]
2008-06-03 16:47 ` Jan Kiszka
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=20080603142947.115490@domain.hid \
--to=karl-trampe@domain.hid \
--cc=mathias_koehrer@domain.hid \
--cc=xenomai@xenomai.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 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.