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Linux for little systems

Posted Dec 18, 2003 9:35 UTC (Thu) by gnb (subscriber, #5132)
In reply to: Linux for little systems by flewellyn
Parent article: Linux for little systems

>Some benchmarks in this area alone would be interesting.
Yes, provided they were for a system very like the one you cared about. The trouble
is there is no one right answer for a kernel expected to run on everything from
an ARM with 8k + 8k of L1 cache and nothing else to a Xeon that can probably
get the whole kernel into L2.

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Posted Dec 18, 2003 9:49 UTC (Thu) by phip (guest, #1715) [Link]

Or a PA-RISC that has 1.5M + 750K L1 (D & I respectively) cache and nothing else...

Linux for little systems

Posted Dec 30, 2003 21:30 UTC (Tue) by joern_engel (guest, #4663) [Link]

Actually, cache size shouldn't matter too much, as it is de-facto zero anyway.

Unless things go horribly wrong, most CPU-time is spend in userspace, not in the kernel. Therefore, the userspace will flush out most kernel instructions from the cache before switching to kernelspace again. Therefore, the cache is always cold, when it comes to the kernel.

With a cold cache, smaller code is also faster code. Your bottle-neck is the memory-bus.