Date: Wed, 17 Nov 2010 16:58:08 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Avi Kivity <avi@redhat.com>
cc: Tom Zanussi <tzanussi@gmail.com>, Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@elte.hu>, "Ted Ts'o" <tytso@mit.edu>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Arjan van de Ven <arjan@infradead.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Li Zefan <lizf@cn.fujitsu.com>, Jason Baron <jbaron@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Christoph Hellwig <hch@lst.de>, Pekka Enberg <penberg@kernel.org>,
        Lai Jiangshan <laijs@cn.fujitsu.com>,
        Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [ANNOUNCE] New utility: 'trace'
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On Wed, 17 Nov 2010, Avi Kivity wrote:

> On 11/17/2010 05:41 PM, Tom Zanussi wrote:
> > 
> > > The only reason why these filters might make sense is to reduce the
> > > trace volume on system wide traces in production environments, but
> > > that's a completely different story. These scenarios can do with the
> > > dynamic tracepoint stuff and the custom filtering w/o putting the
> > > burden on the majority of users.
> > > 
> > Yeah, in my mind, the main point of the filters was to be a 'blunt
> > force' instrument preventing userspace from being overwhelmed by events.
> > The real filtering would happen in userspace with e.g. real scripting
> > languages.
> > 
> 
> Filtering is also useful for fine-grained perf events; this cannot be done in
> userspace.

Could you explain that a bit more detailed please ?

Thanks,

	tglx
 
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