Re: speed difference between using hard-linked and modular drives?

Alan Cox
2001-11-09T12:52:37Z

> Oh no, not this again...
>
> It _IS_ a big deal. Fetching _ONE_ hash chain cache line
> is always going to be cheaper than fetching _FIVE_ to _TEN_
> page struct cache lines while walking the list.

Big picture time. What costs more - the odd five cache line hit or swapping
200Kbytes/second on and off disk ? - thats obviously workload dependant.

Perhaps at some point we need to accept there is a memory/speed tradeoff
throughout the kernel and we need a CONFIG option for it - especially for
the handheld world. I don't want to do lots of I/O on an ipaq, I don't need
big tcp hashes, and I'd rather take a small performance hit.