Hi, all.
I'm still coding in C for all my compute intensive EDA applications
after all these years, and here's why. I've recently benchmarked
DataDraw (datadraw.sf.ne t) graph databases vs GNU C++ graphs built
using STL lists. Large graphs (4 million nodes) were built in the
shape of a mesh. Then, simple depth first traversals were performed
starting from a corner, a hundred times.
The C/DataDraw based implementation ran 15X faster than the C++/STL
version, while using less than half the memory.
The performance difference is due mostly to cache-optimized memory
organization, which gave the DataDraw version a 16.7X lower L2 cache
miss rate, according to cachegrind. I estimate the DataDraw version
achieved around 30X higher useful information density in the cache.
This is due to several factors, which are roughly:
Keeping like data fields together, rather than object fields: 4X
Using a memory pool per field, rather than a global pool: 2X
Using 32-bit object references rather than 64-bit pointers: 2X
Embedding next pointers in edges rather than allocating link object:
2X
In short, C still provides the low-level manipulation hooks to write
ultra-high-performance code, while C++ add-ons have gone down a road
towards mediocre performance. The benchmarks can be found in the
expamples/graph_benchmark directory of the source code, which can be
checked out with:
svn co https://datadraw.svn.sourceforge.net...datadraw/trunk
datadraw
Best regards,
Bill
I'm still coding in C for all my compute intensive EDA applications
after all these years, and here's why. I've recently benchmarked
DataDraw (datadraw.sf.ne t) graph databases vs GNU C++ graphs built
using STL lists. Large graphs (4 million nodes) were built in the
shape of a mesh. Then, simple depth first traversals were performed
starting from a corner, a hundred times.
The C/DataDraw based implementation ran 15X faster than the C++/STL
version, while using less than half the memory.
The performance difference is due mostly to cache-optimized memory
organization, which gave the DataDraw version a 16.7X lower L2 cache
miss rate, according to cachegrind. I estimate the DataDraw version
achieved around 30X higher useful information density in the cache.
This is due to several factors, which are roughly:
Keeping like data fields together, rather than object fields: 4X
Using a memory pool per field, rather than a global pool: 2X
Using 32-bit object references rather than 64-bit pointers: 2X
Embedding next pointers in edges rather than allocating link object:
2X
In short, C still provides the low-level manipulation hooks to write
ultra-high-performance code, while C++ add-ons have gone down a road
towards mediocre performance. The benchmarks can be found in the
expamples/graph_benchmark directory of the source code, which can be
checked out with:
svn co https://datadraw.svn.sourceforge.net...datadraw/trunk
datadraw
Best regards,
Bill