Help required for efficient usage of Cache in DM6437

Simple CbYCrY conversion to Grayscale Image(only Y) takes 8 MIPS. Help needed how to optimize using cache I am attaching sample code for your reference

pucInTemp - Input Buffer

pucOutTemp - Output Buffer

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pucInTemp = pInputBuffer+1;

 for(uiCount = 0; uiCount <720*480; uiCount++)
 {
         *pucOutTemp = *pucInTemp;
        pucOutTemp++; 

         pucInTemp = pucInTemp+2;
 }