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From: Roland McGrath <roland@redhat.com>
To: "Frank Ch. Eigler" <fche@redhat.com>
Cc: systemtap@sources.redhat.com, utrace-devel@redhat.com
Subject: Re: syscall tracing overheads: utrace vs. kprobes
Date: Tue, 28 Apr 2009 18:45:00 -0000	[thread overview]
Message-ID: <20090428181842.93694FC3C6@magilla.sf.frob.com> (raw)
In-Reply-To: Frank Ch. Eigler's message of  Tuesday, 28 April 2009 14:16:39 -0400 <20090428181639.GD13893@redhat.com>

> Certainly, in general.  But in this specific test, only the under-test
> system calls occurred in essnetially the whole system, so the overhead
> measurements were in a way the bare minimums imposed by the kprobes
> vs. utrace callback infrastructure itself.

Yes.  That's why I meant to explain how these numbers are true but not
necessarily the numbers that matter.

> > In real situations [...]  the distribution of overheads will be
> > quite different.
> 
> Or rather, the basic overhead quanta measured above may be multiplied
> along several different axes.

Yes.

  reply	other threads:[~2009-04-28 18:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-28 17:01 Frank Ch. Eigler
2009-04-28 18:10 ` Roland McGrath
2009-04-28 18:16   ` Frank Ch. Eigler
2009-04-28 18:45     ` Roland McGrath [this message]
2009-04-28 18:19 ` David Smith

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