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How is PAE a "really awful hack"? As soon as your processor has a MMU there is neither any "hack" involved nor do you pay any performance penalty. And if your
by sprash 11y ago
How is PAE a "really awful hack"? As soon as your processor has a MMU there is neither any "hack" involved nor do you pay any performance penalty.
And if your app really needs more than 4GB of memory it might be sensible to fork() anyways since unix processes are dirt cheap. It also plays well with modern multicore architectures since it forces you to parallelize your problem.
The single most important performance issue we have today is really memory bandwidth and access time. If you carry 64 bit pointers around all the time you need roughly 30% percent more memory which is wasted on precious cache. So you have to either live with even more cache misses or you have to increase the cache size. And since cache is one of the major power and chip area consumer in todays processors increasing the cache is expensive in many ways.
- zurn 11y agoA performance penalty and kernel memory management complexity comes from peripherals and kernel's inability to directly address all memory and resulting need for bounce buffers. Liked it was with ISA dma 16mb limitation and Linux in the bad old days.
- dezgeg 11y agoYou don't need PAE/LPAE to get to the situation where the kernel can't directly address all physical memory. That point is reached at ~900 MB, after which you need to compile the kernel with HIGHMEM support.