What about Memory Access on another NUMA Node?
What about SSD?
Does a mobile phone programmer need to know the access time for disks?
Does an embedded system programmer need to know anything of these numbers?
Every programmer should know what memory hierarchy and network latency is. (If you learn it by looking at these numbers, fine...)
L3 is generally on the order of the same time as main memory - it's main purpose is to reduce the total amount of requests in order to conserve bandwidth
SSDs are on the order of 0.1ms, so 100,000 ns, give or take a factor of 10.
Someone smarter than me will have to answer the NUMA node question.
L3 CACHE hit, line unshared ~40 cycles
L3 CACHE hit, shared line in another core ~65 cycles
L3 CACHE hit, modified in another core ~75 cycles
remote L3 CACHE ~100-300 cycles
Local Dram ~60 ns
Remote Dram ~100 ns
1: http://software.intel.com/sites/products/collateral/hpc/vtun...
I was trying to make the point that these numbers are somewhat arbitrary (i.e. why do I need to know the access speed to disc, when I keep everything in memory on a NUMA system?) and don't apply to all programmers (e.g. embedded systems may not have discs, L2 Caches or internet access).