Re: [Gnu-arch-users] New feature at the mirror + request for help

[Mikhael Goikhman]

On 24 Mar 2004 03:11:42 +0100, Johannes Berg wrote:
> 
> On Wed, 2004-03-24 at 02:57, Mikhael Goikhman wrote:
> > I believe that the best solution is the smart library, the one that keeps
> > the recently accessed revisions and removes the less requested ones.
> > Smart cache is a very good solution too, it is easier to implement and
> > it is faster, however it may require more disk space.
> 
> What kind of cache algorithm do you want to implement? LRU is probably
> not a good idea for the expected usage pattern (somebody browses stuff
> that rarely anyone looks at, that should not kill other stuff from the
> cache etc...)
> Take a look at ARC (google:ARC IBM cache), but it has a fixed page size
> which is inappropriate here.

I prefer to skip details for now. It may be a mix of LRU (recent) and
LFU (frequent). The LFU alone seems to be problematic as once you have
only pages with high view number in the cache they will stay forever.
We may need some reserved window for LRU entries to solve this.

If someone wishes to design the detailed algorithm, I may probably use
it. Maybe I am an over optimistic, but caching static pages seems pretty
straightforward. Just store url/time/freq/size and the pages themselves.
Starting implementation with pure LRU and incrementally adding LFU sounds
like one possible solution.

A bigger issue to solve is to implement transactional access to cache.

Regards,
Mikhael.