public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Chris Friesen <cfriesen@nortel.com>
To: Puneet Kaushik <puneet_kaushik@persistent.co.in>
Cc: george@mvista.com, kernel-stuff@comcast.net,
	linux-kernel@vger.kernel.org
Subject: Re: Needed faster implementation of do_gettimeofday()
Date: Tue, 22 Feb 2005 09:46:28 -0600	[thread overview]
Message-ID: <421B53D4.3020006@nortel.com> (raw)
In-Reply-To: <1109080575.21544.264.camel@ps2335.persistent.co.in>

Puneet Kaushik wrote:
> Hello Parag and George,
> 
> Thanks for immediate reply.
> The main problem is I am working on a SMP system. I have written a small
> program that just calls the gettimeofday(), one billion times. I have
> run it with time utility and it takes almost double time on SMP then a
> UP.

If the hardware is known in advance, can you use some arch-specific 
thing (like rdtsc on intel) to get a timestamp that can then be 
calibrated by calling gettimeofday() at a lower frequency?

There will be issues (may have to use cpu affinity if the two don't run 
at the same rate, may need to disable any frequency stepping), but it 
might be possible to work around them.

Chris

  reply	other threads:[~2005-02-22 15:47 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-02-20 10:58 Needed faster implementation of do_gettimeofday() puneet_kaushik
2005-02-20 15:48 ` Parag Warudkar
2005-02-22  3:06   ` George Anzinger
2005-02-22 13:56     ` Puneet Kaushik
2005-02-22 15:46       ` Chris Friesen [this message]
2005-02-22 16:44       ` George Anzinger

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=421B53D4.3020006@nortel.com \
    --to=cfriesen@nortel.com \
    --cc=george@mvista.com \
    --cc=kernel-stuff@comcast.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=puneet_kaushik@persistent.co.in \
    /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