Question

Shark, Apple’s profiler which let you configure custom performance counters, is no longer supported in OSX Mountain Lion since it can’t run a 32-bit kernel. Instruments.app, Apple’s replacement for Shark, doesn’t seem to support reading performance counters such as L1 cache hits/misses**. Is there anyway to actually setup and read performance counters on OS X? Even if there is no application, is there some user-land API to do this?

**Instruments.app does seem to have an interface for performance counters, but on my Retina MacBook Pro, the PM Events window lists no events, and indicates “Device: Unknown.” Are there any other alternatives to Instruments?

Answer 1

Yes. It’s there, but difficult to find and clumsy to use (ver.4.5).

• Launch Instruments.
• You are greeted by the Wizard
• Choose “Blank” template for OS X
• Press cmd+L to display the Library
• Add “Counters” instrument to your Instruments document
• Press cmd+shf+P — you are presented with the PM Events floating window.
• Let’s evaluate “Divide Operations executed” — Add “Divide Operations executed” to the PM Events window’s search field.
• Now set the “State” of “Divide Operations executed” to “Visible”
• Now back to the main document window, press cmd+I to display the info popover of the “Counters” instrument.
• Press the + button
• Set the new Counter’s event to “Divide Operations executed”
• Begin sampling…
• End sampling…

You will see the results in Instruments’ table columns. Of course, there are many events you could record — So find the L1 cache events you are interested in and add them instead of divides.

Also be prepared for system freezes (one happened while writing this up).