On 07/23/2012 05:04 AM, Lubos Lunak wrote:
Where's the benchmark for that? I'd like to see what difference it makes, but
I cannot find anything in the blog post.
Good question. I didn't put benchmark data in because I wanted to first
get the background story out first, which I knew was going to be
somewhat long. I'll do another blog post just for benchmarks, and for
other performance considerations.
Having said that, I have _some_ numbers to share. While I can't really
test the real spreadsheet storage benchmark since doing that would
require we actually put this structure into ScColumn for real), we can
simulate it by using the former matrix backend container
mixed_type_matrix, and compare it to multi_type_matrix which uses
multi_type_vector as its backend storage. mixed_type_matrix also had
its elements allocated on the heap and their memory locations stored in
its primary array, so it had the same weakness as the current cell
storage model in ScColumn.
Here are the numbers. The test scenario is to 1) create a 100,000 by
1,000 matrix instance and fill it with numeric values, and 2) iterate
through all its elements and calculate their total. The results are:
mixed_type_matrix:
1) 0.887776 sec
2) 1.96097 sec
multi_type_matrix:
1) 0.819243 sec
2) 0.364899 sec
The instantiation and insertion performance is only slightly faster, but
element iteration performance is noticeably faster with multi_type_matrix.
The test code was compiled with g++ with only -Os flag. I haven't
tested it with any other optimization flags that gcc provides.
Best,
Kohei
--
Kohei Yoshida, LibreOffice hacker, Calc
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