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Writing to non cachable memory is taking less cycles than writing to cachable memory.

Question asked by sunil on Jun 16, 2009
Latest reply on Jul 16, 2009 by joerg



      We have tested a simple asm code of writing zeros to a buffer of size 16KB, which is in SDRAM on BF-533 Ez-Kit Lite. Here we are giving cycles for different modes of caching.


Cache ModeCycles
No cache171283
Cache with Write Back Mode361486
Cache with write through ( Cache lines for reading & Writing)385165
Cache with Write Through ( Cache lines only for reading)171544


From above table we observed that,


                      1. Writing to non cachble memory is taking lesser cycles than writing to cachable memory.

                      2. Write back is consuming more cycles than write through

                      3. In write through, when cache line snot alloacted for writing is taking less cycles than allocating cache lines for writing


  Please share your views on this.