Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 13 Dec 2012 09:02:50 -0800 | Subject | Re: [GIT PULL] perf changes for v3.8 |
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Btw, I do *not* think that you should necessariyl default to 'H' for host-only mode.
The way it should work is that ":pp", ":ppH" and ":ppV" are all different.
- "cycles:ppH" means: I want precise cycles only for the host case
- "cycles:ppV" means: I want precise cycles, and I want the VM too
This would result in EOPNOTSUPP for the case we know is buggy (but presumably work on some other CPUs that don't have the problem)
- "cycles:pp" is "I want precise cycles, and I don't care about virtualization"
This would do whatever works. So it would basically become host-only, but if you don't want precise cycles (so no ":pp") then whatever our old behavior was (presumably "profile the virtual machine too") would be what happens.
That sounds like (a) the interface that people want and (b) entirely backwards-compatible for all cases that can matter (where "oops, I crashed the VM" case does not matter).
Linus
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