52 lines
1.4 KiB
Markdown
52 lines
1.4 KiB
Markdown
|
# Simple/stupid benchmarking
|
||
|
|
|
||
|
|
Compares the string builder and numberToString() function as provided by c++utilities
|
||
|
|
with std::stringstream (without reserving stringstream buffer).
|
||
|
|
|
||
|
|
The string builder is actually just a fancy syntax for std::string::reserve()
|
||
|
|
making its use more convenient.
|
||
|
|
|
||
|
|
## Compile and run
|
||
|
|
|
||
|
|
eg.
|
||
|
|
```
|
||
|
|
g++ -O3 stringbuilder-bench.cpp -o stringbuilder-bench-O3 -Wl,-rpath /lib/path -L /lib/path -lc++utilities
|
||
|
|
./stringbuilder-bench-O3
|
||
|
|
```
|
||
|
|
|
||
|
|
## Results on my machine
|
||
|
|
|
||
|
|
Results with -03:
|
||
|
|
|
||
|
|
```
|
||
|
|
plus operator: 00:00:17
|
||
|
|
stringstream: 00:00:16
|
||
|
|
string builder: 00:00:07
|
||
|
|
diff (stringstream minus string builder): 00:00:09
|
||
|
|
factor (stringstream / string builder): 2.28571
|
||
|
|
```
|
||
|
|
|
||
|
|
However, with -O0 4 times *slower*:
|
||
|
|
|
||
|
|
```
|
||
|
|
plus operator: 00:00:29
|
||
|
|
stringstream: 00:00:16
|
||
|
|
string builder: 00:01:04
|
||
|
|
diff (stringstream minus string builder): - 00:35:22
|
||
|
|
factor (stringstream / string builder): 0.25
|
||
|
|
```
|
||
|
|
|
||
|
|
Still 1.45 times faster than stringstream with -O2:
|
||
|
|
|
||
|
|
```
|
||
|
|
plus operator: 00:00:21
|
||
|
|
stringstream: 00:00:16
|
||
|
|
string builder: 00:00:11
|
||
|
|
diff (stringstream minus string builder): 00:00:05
|
||
|
|
factor (stringstream / string builder): 1.45455
|
||
|
|
```
|
||
|
|
|
||
|
|
So this basic tests show that string builder is up to 2 times faster when using full optimization
|
||
|
|
and still 1.4 times faster when using -O2 (default under Arch Linux). However, this templating
|
||
|
|
stuff completely relies on optimization (as expected). Results with clang++ where similar.
|