Out-of-lining spinlocks [LWN.net]

Out-of-lining spinlocks

Posted Aug 12, 2004 9:16 UTC (Thu) by rjw (guest, #10415)
Parent article: Out-of-lining spinlocks

Surely that is an issue better solved by the profiling tools ( ie allowing certain functions cost to be assigned to their callers) rather than making your code fit the tool?

I'd be really surprised if no profiling tools allowed that.

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Out-of-lining spinlocks

Posted Aug 12, 2004 15:10 UTC (Thu) by jmshh (guest, #8257) [Link]

The issue is better solved by the profiling tools, but for most architectures they don't know how to identify the caller. The missing item is the return address.

There are two solutions:

Compile the code with using a frame pointer (FP) for each routine. For most architectures (especially register starved ones like x86) the code will be significantly larger and slower.
Analyze the code statically and for every possible PC calculate an offset from SP where the return address is found. This requires a dissassembler in the tool.