Texas Instruments SPRAA56 appendix Expected Values for the STS Objects

SPRAA56

Figure 7. Statistics View Showing Benchmark Measurements

Look at both the average values and the maximum values to see how the application benchmarks are performing.

Note that STS objects hold 32-bit values on the target DSP. The values accumulated on the host PC are 64-bit values. The values on the target DSP are reset to zero when the host PC polls them for data. So, it is possible for the total value to overflow and restart at zero if you choose a slow update rate for the Statistics View in CCStudio. The maximum value is still accurate even if the total overflows. The average value is calculated on the host PC, and is not stored in the STS objects on the target DSP.

5.3.1 Expected Values for the STS Objects

Table 1 shows expected and measured values for the STS benchmarks in the instrumented application. The right column is blank in case you want to fill in your own measurements.

stsInVidPeriod, stsOutVidPeriod, and stsProcPeriod are all expected to be 33.33 ms, because this is the amount of time between successive frames in an NTSC video system.

The stsInVidTotal, stsOutVidTotal, and stsProcTotal values are expected to be slightly more than the sum of the Cell functions in each task, because the API calls are placed around a larger block than just the algorithm execution calls. The total values do not include time waiting on blocking calls like FVID_exchange or SCOM_getMsg, however.

The waiting time for the input and output tasks (stsInVidWait0 and stsOutVidWait0) are expected to be some value less than 33 ms, with a longer waiting time for the display than for the input.

DSP/BIOS Real-Time Analysis (RTA) and Debugging Applied to a Video Application 23