From: "David S. Miller" <davem@redhat.com>
To: ak@suse.de
Cc: jamesclv@us.ibm.com, alan@lxorguk.ukuu.org.uk,
linux-kernel@vger.kernel.org, johnstul@us.ibm.com,
anton.wilson@camotion.com
Subject: Re: do_gettimeofday vs. rdtsc in the scheduler
Date: Tue, 17 Sep 2002 15:38:28 -0700 (PDT) [thread overview]
Message-ID: <20020917.153828.24171342.davem@redhat.com> (raw)
In-Reply-To: <20020918004442.A32234@wotan.suse.de>
From: Andi Kleen <ak@suse.de>
Date: Wed, 18 Sep 2002 00:44:42 +0200
> I don't know how Sun and SGI manage with their larger systems. Either they
> don't do clock sync, or they may have to make expensive tradeoffs.
I guess you could always run NTP between the different CPUs ;) ;)
:-)
More seriously, you don't need to have the cpu tick registers sync'd,
it is the rate that matters.
Once booted, you can sync these system tick registers with a pretty
straight forward algorithm in the kernel. Bonus points if you can
figure out how to cancel out the cost of moving the system tick sample
cachelines between master and slave in your algorithm :-)
next prev parent reply other threads:[~2002-09-17 22:42 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200209172020.g8HKKPF13227@eng2.beaverton.ibm.com.suse.lists.linux.kernel>
[not found] ` <1032294559.22815.180.camel@cog.suse.lists.linux.kernel>
[not found] ` <20020917.133933.69057655.davem@redhat.com.suse.lists.linux.kernel>
2002-09-17 21:00 ` Andi Kleen
2002-09-17 20:54 ` David S. Miller
2002-09-17 21:28 ` Alan Cox
2002-09-17 21:18 ` David S. Miller
2002-09-17 22:02 ` James Cleverdon
2002-09-17 22:44 ` Andi Kleen
2002-09-17 22:38 ` David S. Miller [this message]
2002-09-17 22:55 ` James Cleverdon
2002-09-17 23:12 ` David S. Miller
2002-09-17 23:32 ` john stultz
2002-09-17 23:32 ` David S. Miller
2002-09-17 23:52 ` Andi Kleen
2002-09-17 23:46 ` David S. Miller
2002-09-17 23:58 ` Andi Kleen
2002-09-17 23:51 ` David S. Miller
2002-09-18 0:05 ` Andi Kleen
2002-09-18 1:04 ` James Cleverdon
2002-09-19 18:02 ` Andrea Arcangeli
2002-09-20 11:04 ` Maciej W. Rozycki
2002-09-19 11:20 ` Mikael Pettersson
2002-09-19 13:27 ` Alan Cox
2002-09-19 13:39 ` Mikael Pettersson
2002-09-20 15:26 ` John Levon
2002-09-18 6:40 ` Vojtech Pavlik
2002-09-19 18:04 ` Andrea Arcangeli
[not found] <200209172020.g8HKKPF13227@eng2.beaverton.ibm.com>
2002-09-17 20:29 ` Fwd: " john stultz
2002-09-17 20:39 ` David S. Miller
2002-09-17 20:57 ` john stultz
2002-09-17 20:56 ` David S. Miller
2002-09-09 22:21 anton wilson
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