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From: "fche at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sources.redhat.com
Subject: [Bug runtime/3916] improve timing monotony
Date: Wed, 24 Jan 2007 19:32:00 -0000	[thread overview]
Message-ID: <20070124193224.20288.qmail@sourceware.org> (raw)
In-Reply-To: <20070124160955.3916.fche@redhat.com>


------- Additional Comments From fche at redhat dot com  2007-01-24 19:32 -------
(In reply to comment #1)
> Possible solutions:
> * Find a better estimate of the cpu freq
> * Use a clock that's independent of cpu freq (e.g., a motherboard/chipset timer)
> * Get the kernel to provide a lockless gettimeofday
> * Others?

One simple thing is to keep the per-cpu counts from ever decreasing during
the resynchronization phase.  This could let them drift ahead of real time,
but so be it.  If it gets too bad, the runtime could emit a warning.
Also, the resync phase may not be necessary so frequently on stable_tsc
processors.

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=3916

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  parent reply	other threads:[~2007-01-24 19:32 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-24 16:10 [Bug runtime/3916] New: " fche at redhat dot com
2007-01-24 18:52 ` [Bug runtime/3916] " joshua dot i dot stone at intel dot com
2007-01-24 19:13 ` joshua dot i dot stone at intel dot com
2007-01-24 19:32 ` fche at redhat dot com [this message]
2007-06-07  2:15 ` joshua dot i dot stone at intel dot com
2007-08-15  9:10 ` mhiramat at redhat dot com
2007-08-15 15:11 ` mhiramat at redhat dot com
2007-08-16 18:17 ` joshua dot i dot stone at intel dot com

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