+ Attempts to retrieve a performance measurement log entry from the performance measurement log. \r
+ It can also retrieve the log created by StartPerformanceMeasurementEx and EndPerformanceMeasurementEx,\r
+ and then eliminate the Identifier.\r
+\r
+ Attempts to retrieve the performance log entry specified by LogEntryKey. If LogEntryKey is\r
+ zero on entry, then an attempt is made to retrieve the first entry from the performance log,\r
+ and the key for the second entry in the log is returned. If the performance log is empty,\r
+ then no entry is retrieved and zero is returned. If LogEntryKey is not zero, then the performance\r
+ log entry associated with LogEntryKey is retrieved, and the key for the next entry in the log is\r
+ returned. If LogEntryKey is the key for the last entry in the log, then the last log entry is\r
+ retrieved and an implementation specific non-zero key value that specifies the end of the performance\r
+ log is returned. If LogEntryKey is equal this implementation specific non-zero key value, then no entry\r
+ is retrieved and zero is returned. In the cases where a performance log entry can be returned,\r
+ the log entry is returned in Handle, Token, Module, StartTimeStamp, and EndTimeStamp.\r
+ If LogEntryKey is not a valid log entry key for the performance measurement log, then ASSERT().\r
+ If Handle is NULL, then ASSERT().\r
+ If Token is NULL, then ASSERT().\r
+ If Module is NULL, then ASSERT().\r
+ If StartTimeStamp is NULL, then ASSERT().\r
+ If EndTimeStamp is NULL, then ASSERT().\r
+\r
+ @param LogEntryKey On entry, the key of the performance measurement log entry to retrieve.\r
+ 0, then the first performance measurement log entry is retrieved.\r
+ On exit, the key of the next performance lof entry entry.\r
+ @param Handle Pointer to environment specific context used to identify the component\r
+ being measured. \r
+ @param Token Pointer to a Null-terminated ASCII string that identifies the component\r
+ being measured. \r
+ @param Module Pointer to a Null-terminated ASCII string that identifies the module\r
+ being measured.\r
+ @param StartTimeStamp Pointer to the 64-bit time stamp that was recorded when the measurement\r
+ was started.\r
+ @param EndTimeStamp Pointer to the 64-bit time stamp that was recorded when the measurement\r
+ was ended.\r
+\r
+ @return The key for the next performance log entry (in general case).\r
+\r
+**/\r
+UINTN\r
+EFIAPI\r
+GetPerformanceMeasurement (\r
+ IN UINTN LogEntryKey, \r
+ OUT CONST VOID **Handle,\r
+ OUT CONST CHAR8 **Token,\r
+ OUT CONST CHAR8 **Module,\r
+ OUT UINT64 *StartTimeStamp,\r
+ OUT UINT64 *EndTimeStamp\r
+ );\r
+\r
+/**\r
+ Creates a record for the beginning of a performance measurement.\r
+\r
+ Creates a record that contains the Handle, Token, Module and Identifier.\r
+ If TimeStamp is not zero, then TimeStamp is added to the record as the start time.\r
+ If TimeStamp is zero, then this function reads the current time stamp\r
+ and adds that time stamp value to the record as the start time.\r
+\r
+ @param Handle Pointer to environment specific context used\r
+ to identify the component being measured.\r
+ @param Token Pointer to a Null-terminated ASCII string\r
+ that identifies the component being measured.\r
+ @param Module Pointer to a Null-terminated ASCII string\r
+ that identifies the module being measured.\r
+ @param TimeStamp 64-bit time stamp.\r
+ @param Identifier 32-bit identifier. If the value is 0, the created record\r
+ is same as the one created by StartPerformanceMeasurement.\r
+\r
+ @retval RETURN_SUCCESS The start of the measurement was recorded.\r
+ @retval RETURN_OUT_OF_RESOURCES There are not enough resources to record the measurement.\r
+ @retval RETURN_DEVICE_ERROR A device error reading the time stamp.\r
+\r
+**/\r
+RETURN_STATUS\r
+EFIAPI\r
+StartPerformanceMeasurementEx (\r
+ IN CONST VOID *Handle, OPTIONAL\r
+ IN CONST CHAR8 *Token, OPTIONAL\r
+ IN CONST CHAR8 *Module, OPTIONAL\r
+ IN UINT64 TimeStamp,\r
+ IN UINT32 Identifier\r
+ );\r
+\r
+/**\r
+ Fills in the end time of a performance measurement.\r
+\r
+ Looks up the record that matches Handle, Token and Module.\r