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

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Fri Nov 09 2001 - 07:59:09 EST


> 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.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Thu Nov 15 2001 - 21:00:22 EST