|| ||Ingo Molnar <mingo-AT-elte.hu> |
|| ||Avi Kivity <avi-AT-redhat.com> |
|| ||Re: [RFC] Unify KVM kernel-space and user-space code into a single project |
|| ||Mon, 22 Mar 2010 12:23:40 +0100|
|| ||Anthony Liguori <anthony-AT-codemonkey.ws>,
Pekka Enberg <penberg-AT-cs.helsinki.fi>,
"Zhang, Yanmin" <yanmin_zhang-AT-linux.intel.com>,
Peter Zijlstra <a.p.zijlstra-AT-chello.nl>,
Sheng Yang <sheng-AT-linux.intel.com>,
Marcelo Tosatti <mtosatti-AT-redhat.com>,
oerg Roedel <joro-AT-8bytes.org>,
Jes Sorensen <Jes.Sorensen-AT-redhat.com>,
Gleb Natapov <gleb-AT-redhat.com>,
Zachary Amsden <zamsden-AT-redhat.com>, ziteng.huang-AT-intel.com,
Arnaldo Carvalho de Melo <acme-AT-redhat.com>,
Fr?d?ric Weisbecker <fweisbec-AT-gmail.com>|
|| ||Article, Thread
* Avi Kivity <email@example.com> wrote:
> IMO the reason perf is more usable than oprofile has less to do with the
> kernel/userspace boundary and more do to with effort and attention spent on
> the userspace/user boundary.
If you are interested in the first-hand experience of the people who are doing
the perf work then here it is: by far the biggest reason for perf success and
perf usability is the integration of the user-space tooling with the
kernel-space bits, into a single repository and project.
The very move you are opposing so vehemently for KVM.
Oprofile went the way you proposed, and it was a failure. It failed not
because it was bad technology (it was pretty decent and people used it), it
was not a failure because the wrong people worked on it (to the contrary, very
capable people worked on it), it was a failure in hindsight because it simply
incorrectly split into two projects which stiffled the progress of each other.
Obviously 3 years ago you'd have seen a similar, big "Oprofile is NOT broken!"
flamewar, had i posted the same observations about Oprofile that i expressed
about KVM here. (In fact there was a similar, big flamewar about all this when
perf was posted a year ago.)
And yes, (as you are aware of) i see very similar patterns of inefficiency in
the KVM/Qemu tooling relationship as well, hence did i express my views about
to post comments)