FS#1305Bottleneck in DL_Dxf::toReal caused by std::locale
- Type
- Performance Issue
- Status
- Closed
- Resolution
- Implemented
- Category
- dxflib
- Severity
- Low
- Priority
- Low
- Reported version
- 3.12.1
- Operating system
- All
- Reported
- 2015-11-20 by mzeilfelder
- Closed
- 2015-12-15 by andrew
Loading any larger dxf file takes very long because of this line:
istr.imbue(std::locale("C"));
The call to std::locale is very slow. File-loading can be speed up by approximately factor 5 times on my system when replacing it. I just removed that line and instead added the following in DL_Dxf::in so it is changed only once per file:
std::locale oldLocale = std::locale::global(std::locale("C")); // use dot in numbers
while (readDxfGroups(fp, creationInterface)) {}
std::locale::global(oldLocale);
Comments (2)
Thanks for your suggestion.
Needs serious testing on several platforms. Note that an error in this part has very bad consequences (slightly wrong, rounded coordinates when loading DXF files).
Conversion still uses the same locale, just once instead of every time. There isn't another call in the lib to set the locale so far, so shouldn't be reset in between. Some risk if people use it in a thread while changing the locale in another thread at the same time I guess. And maybe some risk in case you have other functions in loading which depend on the locale. Like for example if you create strings somewhere which should use the users locale instead.
But definitely worth it for speed. I'm currently evaluating the lib and it makes a lot of difference in development since I no longer have to wait > 10 seconds each time I load my test-models :-)
Btw, I used the tool "Very sleepy" to find this, highly recommended in case you haven't run into it yet!