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Published 20 hours ago • verified publisher icon ssvb

memory latency SIZE overflow

Open mpetri opened this issue 12 years ago • 2 comments

I have a system with lots of ram (1.5TB) and I want to use this tool to test the memory latency when accessing different NUMA nodes. unfortunately the block SIZE variable overflows as it is stored in a integer instead of a 64bit value.

mpetri avatar Sep 23 '13 15:09 mpetri

That's interesting. This tool had been primarily developed for use on the embedded ARM/MIPS systems to spot the oddities/misconfiguration in the memory subsystem. I never imagined that anyone would run it on big servers :)

About the SIZE variable limitation. There is one more problem to solve: currently 32-bit http://en.wikipedia.org/wiki/Linear_congruential_generator is used for generating random offsets inside the buffer. This also needs to be reworked a bit. I'll try to see what can be done.

ssvb avatar Sep 24 '13 12:09 ssvb

looking at the wikipedia article of the it looks like the current constants ( 1103515245 and 12345 ) can just be replaced by 6364136223846793005 and 1442695040888963407 respectively.

thanks for the awesome tool by the way. In large server systems memory access is not uniform and I want to use your tool measure the latency between different nodes in the system.

mpetri avatar Sep 24 '13 12:09 mpetri