@ -40,11 +40,22 @@ Build with default optimisations using `make release`, it will output a stripped
* The Makefile uses variables `RELEASE_CFLAGS` and `RELEASE_LDFLAGS` to apply optimisations (and `DEBUG_CFLAGS` + `DEBUG_LDFLAGS` for extra compiler flags with the debug target). If needed you can set these yourself to prevent the defaults.
* The Makefile uses variables `RELEASE_CFLAGS` and `RELEASE_LDFLAGS` to apply optimisations (and `DEBUG_CFLAGS` + `DEBUG_LDFLAGS` for extra compiler flags with the debug target). If needed you can set these yourself to prevent the defaults.
* The default `RELEASE_CFLAGS` specify `-march=native` which may be undesireable for you. Set the variable or modify the Makefile if you need to remove this.
* The default `RELEASE_CFLAGS` specify `-march=native` which may be undesireable for you. Set the variable or modify the Makefile if you need to remove this.
## PGO
Building with Profile Guided Optimisation is supported with the `pgo` Makefile target. It uses the same rules as the `release` target and outputs a binary to `fcmp-pgo`.
There may be small performance improvements from using this target instead of `release`, but the difference is mostly negligable.
## Debug target
## Debug target
Build with debugging information and no optimisations using `make debug`, it will output a binary at `fcmp-debug`.
Build with debugging information and no optimisations using `make debug`, it will output a binary at `fcmp-debug`.
## Note
## Notes
Before switching between `release` and `debug` targets, make sure to run `make clean`.
- Before switching between targets, make sure to run `make clean`.
- GCC + Graphite compiler specific optimisation flags are added by default with the `OPT_FLAGS` variable. Override this variable if using another compiler that doesn't support these optimisations.
### Multithreading
- By default, parallel processing is enabled when building through `libpthread`, to build a single-threaded version override the variables `FEAT_CFLAGS` and `FEAT_LDFLAGS` to empty.
- By default the program will decide at runtime whether or not to use parallelised processing. You can set `FEAT_CFLAGS="-D_RUN_THREADED=1"` to _force_ the use of a parallelised run every time in the binary, although this is not recommended.
- Performance gains from parallelised runs mostly appear with a large number of files being compared at once, as the task delegation overhead is surpassed.
