rixed
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dwelch posted on Sep 25 2006 at 09:29 AM said:I turned on and off dcache and the write buffer. Noticeable difference. The problem appears to be linear, the difference is between N = 2 and N = 4, BUT there is a relationship with the problem and the mask. So that means it isnt necessarily writes 1024 words apart, but some boundary crossing. And this data continues to support that as increasing the N, to 8, 16, 32, etc up to 1024 gradually increases the execution time, the larger the N the sooner and more often that boundary is crossed.
Yes I have the same feeling that we are experiencing crossing a RAM boundary. Something like when you access another bank of RAM some signals "out there" need to be changed or resynchronized, or who knows what.
Im going to play with that base address and the mask to try to find out this "bank" sizes and locations. It's going to be quite small, I fear, because for N=150 we are almost at the maximum latency.
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