MCPS was too high when use C6748 to do Jpeg decode

Hi, all

     I'm using the C6748 to do Jpeg decode, the decode Lib was from TI which version is: v02.00.01.

     I have port  the test code provide by TI which from the install path of jpeg decoder.

     During benchmark, the decode works correctly. But I found that it cost almost 450 MCPS to decode a 1600*1200 jpeg picture, it is too high!!!! I have read the datasheet from TI,  as the description the MCPS should be around 34MCPS! I have get almost 10 times result!!!

     So, I want to ask what's the problem is?

     Following are some detail about my testing situation:

     1, My code were porting from TI's demo code, and run on my C6748 board, that means the code is running on the hardware

     2,  The MCPS I get has exclude the file load cost, just the decode process.

     3, Cache operation were configure and operate as the same as the demo code from TI.