* Avi Kivity <avi@xxxxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
