[PATCH] benchtests: Add malloc microbenchmark

[Steven Munroe]

On Tue, 2014-04-15 at 14:35 +0100, Will Newton wrote:
> Add a microbenchmark for measuring malloc and free performance. The
> benchmark allocates and frees buffers of random sizes in a random
> order and measures the overall execution time and RSS. Variants of the
> benchmark are run with 8, 32 and 64 threads to measure the effect of
> concurrency on allocator performance.
> 
> The random block sizes used follow an inverse square distribution
> which is intended to mimic the behaviour of real applications which
> tend to allocate many more small blocks than large ones.
> 

This test is more likely to measure the locking overhead of random then
it is to measure malloc performance.

Any attempt at defining a new (another) micro-benchmark should profile
to verify that overhead of setup and measurement is small (< 1%)
compared to what you are trying measure.

And verify this on multiple platforms.