Performance Counter Addresses

Robert O'Callahan robert at ocallahan.org
Mon Oct 5 02:05:52 UTC 2015


On Mon, Oct 5, 2015 at 2:52 PM, Downing, Evan P <edowning3 at gatech.edu>
wrote:

> I'm gathering data such as network traffic, plugins installed, files
> downloaded using Firefox, etc.
>
>
> I could just use PANDA, but extracting the information could take a long
> time.
>
> The performance overhead is large.
>

What's PANDA's recording performance overhead?

It would be faster if I used rr to extract preliminary information to
> determine if the data is worth studying more, and then perform an in-depth
> analysis using PANDA.
>
> Sort of like zooming in on the problem (using PANDA) once I've discovered
> it (using rr).
>

For that to work, your best bet is probably to use rr to record a Firefox
session, running the whole thing under QEMU-KVM with PMU enabled. Then
switch the QEMU mode to PANDA, and run rr replay in it. But you would need
to extend QEMU/TCG to support the retired-conditional-branches counter.

Rob
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