Speed memory access by arranging data to take advantage of CPU caching

Re:Speed memory access by arranging data to take advantage o... by assholesRppl2 on Sunday April 06, 2014 @07:33PM (#7543722)

The best cache-aware programming lesson I ever received was in the CS61C course at Berkeley -- building a cache-blocking algorithm to run a matrix multiplication function using the cache as efficiently as possible. We unrolled loops so that the size of each iteration was exactly the size of one cache block, and saw instantly the increase in FLOpS.

Then we did some OpenMP parallelization. That was cool.

Nice post!

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Re:Speed memory access by arranging data to take advantage o... by wting on Sunday April 06, 2014 @11:41PM (#7544517)

I had a similar project in a programming for performance class at UT Austin. We had access to TACC supercomputers and were tasked with finding the CPU's L1 cache size via trial and error. We were testing it by using matrix multiplication and measuring performance output, and changing the chunk sizes accordingly.

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Re:Speed memory access by arranging data to take advantage o... by pkill17 on Sunday April 06, 2014 @08:12PM (#7543885)

61C veteran here too! Those projects were mind blowing at times; unrolling a loop by 2 or even 4 would have ridiculous effects on runtime.

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