diff --git a/docs/source/kernel-library-selective-build.md b/docs/source/kernel-library-selective-build.md
index f9a991767a3..3e9400f4d6a 100644
--- a/docs/source/kernel-library-selective-build.md
+++ b/docs/source/kernel-library-selective-build.md
@@ -36,17 +36,20 @@ The basic flow looks like this:
## APIs
-We expose a CMake macro `[gen_selected_ops](https://github.com/pytorch/executorch/blob/main/tools/cmake/Codegen.cmake#L12)`, to allow users specifying op info:
+We expose a CMake macro [gen_selected_ops](https://github.com/pytorch/executorch/blob/main/tools/cmake/Codegen.cmake#L12), to allow users specifying op info:
```
gen_selected_ops(
- LIB_NAME # the name of the selective build operator library to be generated
- OPS_SCHEMA_YAML # path to a yaml file containing operators to be selected
- ROOT_OPS # comma separated operator names to be selected
- INCLUDE_ALL_OPS # boolean flag to include all operators
+ LIB_NAME # the name of the selective build operator library to be generated
+ OPS_SCHEMA_YAML # path to a yaml file containing operators to be selected
+ ROOT_OPS # comma separated operator names to be selected
+ INCLUDE_ALL_OPS # boolean flag to include all operators
+ OPS_FROM_MODEL # path to a pte file of model to select operators from
+ DTYPE_SELECTIVE_BUILD # boolean flag to enable dtye selection
)
```
+The macro makes a call to gen_oplist.py, which requires a [distinct selection](https://github.com/BujSet/executorch/blob/main/codegen/tools/gen_oplist.py#L222-L228) of API choice. `OPS_SCHEMA_YAML`, `ROOT_OPS`, `INCLUDE_ALL_OPS`, and `OPS_FROM_MODEL` are mutually exclusive options, and should not be used in conjunction.
### Select all ops
@@ -62,31 +65,29 @@ Context: each kernel library is designed to have a yaml file associated with it.
This API lets users pass in a list of operator names. Note that this API can be combined with the API above and we will create a allowlist from the union of both API inputs.
+### Select ops from model
-## Example Walkthrough
+This API lets users pass in a pte file of an exported model. When used, the pte file will be parsed to generate a yaml file that enumerates the operators and dtypes used in the model.
-In CMakeLists.txt we have the following logic:
-```cmake
-set(_kernel_lib)
-if(SELECT_ALL_OPS)
- gen_selected_ops("" "" "${SELECT_ALL_OPS}")
-elseif(SELECT_OPS_LIST)
- gen_selected_ops("" "${SELECT_OPS_LIST}" "")
-elseif(SELECT_OPS_YAML)
- set(_custom_ops_yaml ${EXECUTORCH_ROOT}/examples/portable/custom_ops/custom_ops.yaml)
- gen_selected_ops("${_custom_ops_yaml}" "" "")
-endif()
-```
-Then when calling CMake, we can do:
+### Dtype Selective Build
-```
-cmake -D… -DSELECT_OPS_LIST="aten::add.out,aten::mm.out”
-```
+Beyond pruning the binary to remove unused operators, the binary size can further reduced by removing unused dtypes. For example, if your model only uses floats for the `add` operator, then including variants of the `add` operators for `doubles` and `ints` is unnecessary. The flag `DTYPE_SELECTIVE_BUILD` can be set to `ON` to support this additional optimization. Currently, dtype selective build is only supported with the model API described above. Once enabled, a header file that specifies only the operators and dtypes used by the model is created and linked against a rebuild of the `portable_kernels` lib. This feature is only supported for the portable kernels library; it's not supported for optimized, quantized or custom kernel libraries.
-Or
+## Example Walkthrough
-```
-cmake -D… -DSELECT_OPS_YAML=ON
-```
+In [CMakeLists.txt](https://github.com/BujSet/executorch/blob/main/examples/selective_build/CMakeLists.txt#L48-L72), we have the following cmake config options:
+
+1. `EXECUTORCH_SELECT_OPS_YAML`
+2. `EXECUTORCH_SELECT_OPS_LIST`
+3. `EXECUTORCH_SELECT_ALL_OPS`
+4. `EXECUTORCH_SELECT_OPS_FROM_MODEL`
+5. `EXECUTORCH_DTYPE_SELECTIVE_BUILD`
+
+These options allow a user to tailor the cmake build process to utilize the different APIs, and results in different invocations on the `gen_selected_ops` [function](https://github.com/BujSet/executorch/blob/main/examples/selective_build/CMakeLists.txt#L110-L123). The following table describes some examples of how the invocation changes when these configs are set:
-To select from either an operator name list or a schema yaml from kernel library.
+| Example cmake Call | Resultant `gen_selected_ops` Invocation |
+| :----: | :---:|
+|
cmake -D… -DSELECT_OPS_LIST="aten::add.out,aten::mm.out"
gen_selected_ops("" "${SELECT_OPS_LIST}" "" "" "")
cmake -D… -DSELECT_OPS_YAML=ON
set(_custom_ops_yaml ${EXECUTORCH_ROOT}/examples/portable/custom_ops/custom_ops.yaml)
gen_selected_ops("${_custom_ops_yaml}" "" "")
cmake -D… -DEXECUTORCH_SELECT_OPS_FROM_MODEL="model.pte.out"
gen_selected_ops("" "" "" "${_model_path}" "")
cmake -D… -DEXECUTORCH_SELECT_OPS_FROM_MODEL="model.pte.out" -DEXECUTORCH_DTYPE_SELECTIVE_BUILD=ON
gen_selected_ops("" "" "" "${_model_path}" "ON")