add time api doc

docs/reference/time-api.md

@@ -0,0 +1,80 @@
+---
+outline: deep
+---
+
+# ggml time api
+
+## ggml init time {#initTime}
+
+ggml init instance prepare for other time api.
+
+- **type**
+
+```c++
+ GGML_API void ggml_time_init(void);
+```
+
+- **detail**
+
+Call this once at the beginning of the program
+
+- **example**
+
+```c++
+
+#include "ggml/ggml.h"
+
+void main(){
+ ggml_time_init();
+ //...
+}
+```
+## ggml_time_ms {#timeMillisecond}
+
+Get time in millisecond.
+
+- **type**
+
+```c++
+ GGML_API int64_t ggml_time_ms(void);
+```
+
+- **example**
+
+```c++
+
+#include "ggml/ggml.h"
+
+void main(){
+ ggml_time_init();
+ const auto t_main_start_ms = ggml_time_ms();
+ //...
+ const auto t_main_end_ms = ggml_time_ms();
+ const total = t_main_end_ms-t_main_start_ms;
+}
+```
+
+## ggml_time_us {#timeMicroseconds}
+
+Get time in microseconds.
+
+- **type**
+
+```c++
+ GGML_API int64_t ggml_time_us(void);
+```
+
+- **example**
+
+```c++
+#include "ggml/ggml.h"
+
+void main(){
+ ggml_time_init();
+ const auto t_main_start_us = ggml_time_us();
+ //...
+ const auto t_main_end_us = ggml_time_us();
+ const total = t_main_end_us-t_main_start_us;
+}
+```
+