Initial performance cluster SimpleMessenger vs AsyncMessenger results

[Mark Nelson <mnelson@redhat.com>]

Hi Guy,

Given all of the recent data on how different memory allocator 
configurations improve SimpleMessenger performance (and the effect of 
memory allocators and transparent hugepages on RSS memory usage), I 
thought I'd run some tests looking how AsyncMessenger does in 
comparison.  We spoke about these a bit at the last performance meeting 
but here's the full write up.  The rough conclusion as of right now 
appears to be:

1) AsyncMessenger performance is not dependent on the memory allocator 
like with SimpleMessenger.

2) AsyncMessenger is faster than SimpleMessenger with TCMalloc + 32MB 
(ie default) thread cache.

3) AsyncMessenger is consistently faster than SimpleMessenger for 128K 
random reads.

4) AsyncMessenger is sometimes slower than SimpleMessenger when memory 
allocator optimizations are used.

5) AsyncMessenger currently uses far more RSS memory than SimpleMessenger.

Here's a link to the paper:

https://drive.google.com/file/d/0B2gTBZrkrnpZS1Q4VktjZkhrNHc/view

Mark