More about scalability

[Ramine]

Hello,


If you ask me the following question:


Amine, you have included the data moving part from the memory to the CPU
that is stored in the corresponding key of the concurrent hashtable as a
serial part of the Amdahl equation to calculate the scalability
of the concurrent hashtable, is it correct to do it like this ?


Answer:

When the PhD papers are testing there scalable concurrent hashtable
or scalable Red Black trees, they are testing them just by moving the
pointers of the data of the corresponding keys, they are not counting
the moving of the data of the corresponding keys from the memory
to the CPU, this is why there concurrent hashtables and concurrent
Red Blacks trees are scaling better, but in real world applications
the moving part of the data corresponding to the keys of the concurrent
hashtable or the concurrent Red Black tree from
the memory to the CPU are always taking place and the memory subsystem
are still the bottleneck on today multicore machines and i think
it will still be the bottleneck in a far future for the scalability if
the data on each corresponding key is more bigger, this is why i have
included this serial part inside the Amdahl equation for calculating the
scalability of the concurrent hashtable.



Thank you,
Amine Moulay Ramdane.