Siemens XT75 Manuale Utente
Java User’s Guide
5.12 Performance
49
s
wm_java_usersguide_v12
Page 43 of 123
2008-02-25
Confidential / Released
5.12
Performance
The performance study was focused on comparable performance values under various circum-
stances.
stances.
5.12.1
Java
This section gives information about the Java command execution throughput (“jPS”= Java
statements per second). The scope of this measurement is only the statement execution time,
not the execution delay (Java command on AT interface
statements per second). The scope of this measurement is only the statement execution time,
not the execution delay (Java command on AT interface
→
Java instruction execution
→
reac-
tion on GPIO).
Figure 13: Test case for measuring Java command execution throughput
The following Java instruction was used for calculation of the typical jPS:
value = ( 2 x number of calculation statements ) /
value = ( 2 x number of calculation statements ) /
( (1 / frequencyB ) - ( 1 / frequencyA ) );
Measurement and calculation were done using:
•
•
duration of each loop = 600 s
•
number of calculation statements = 50 “result=(CONSTANT_VALUE/variable_value);”-
Instructions (executed twice per pin cycle)
Instructions (executed twice per pin cycle)
•
frequencyA as measured with a universal counter
•
frequencyB as measured with a universal counter
The reference loop has the same structure as the measurement loop except that the measure-
ment sequence is moved.
ment sequence is moved.
Since only a small amount of Java code is executed in this test, it is easily optimized by the
CLDC’s HI just-in-time compiler. More complex applications might not reach that execution
speed.
CLDC’s HI just-in-time compiler. More complex applications might not reach that execution
speed.
State
jPS-Value (mean)
ME in IDLE mode / Not connected
~49000
CSD connection
~46000