* Avi Kivity <[email protected]> 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
it.
Thanks,
Ingo
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