Re: [RFC 4/5] x86, perf: implements lwp-perf-integration (rc1)

Ingo Molnar
2011-12-21T14:43:16Z

* 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