Re: [Qemu-block] [PATCH] qcow2: Optimize L2 table cache size based on image and cluster sizes

[Alberto Garcia]

On Wed 05 Oct 2016 05:13:39 PM CEST, Max Reitz wrote:

>>>> At least giving users a way to skip the math would be an
>>>> improvement.  Would you be okay with an explicitly-set option like
>>>> l2_cache_size=auto or =max that optimizes for performance at the
>>>> expense of memory?
>>>
>> Frank Myhr's suggestion (in bugzilla) is that we allow specifying a %
>> of the disk size, so
>> 
>> l2-cache-size=100%  (that would be cache-size=max)
>> l2-cache-size=80%

> For me, either works fine.
>
> Apart from that, I have to say I think it would be a bit more useful
> if one would specify the area covered by the metadata caches as an
> absolute number instead of a relative one (I guess it's generally
> easier to know what area your applications will perform random
> accesses on than the relative size, but maybe that's just me).

I'm not sure if I'm following you, can you give an example of what the
area covered by the cache exactly means?

Berto