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Date: Wed, 21 Dec 2011 14:22:33 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Avi Kivity <avi@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>, Robert Richter <robert.richter@amd.com>,
        Benjamin Block <bebl@mageta.org>,
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        linux-kernel@vger.kernel.org, Benjamin Block <benjamin.block@amd.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC 4/5] x86, perf: implements lwp-perf-integration (rc1)
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* Avi Kivity <avi@redhat.com> wrote:

> On 12/21/2011 02:34 PM, Ingo Molnar wrote:
>
> > I think it can all be supported in a consistent way (see my 
> > previous mails) - but the feature as presented today just 
> > does not look useful enough to me if only supports that 
> > niche self-monitoring usecase.
> 
> I hate to re-enter this thread, but this "niche use case" is 
> exactly what LWP is designed for. [...]

It's not the only usecase that it can be used in, and that is 
what matters to me.

> [...] And once the JVM is adapted to exploit LWP, its use will 
> dwarf all of the uses of perf put together (except the NMI 
> watchdog).  You're only causing the developers needless pain 
> by forcing them to fit this red peg into a green hole.

I disagree - i think LWP has been seriously over-sold and 
seriously under-designed. Anyway, i'm willing to be convinced 
that it's worth to be merged upstream, if it brings tangible 
benefits to the usecases i mentioned.

Thanks,

	Ingo