Re: [Qemu-devel] DMG chunk size independence

[Ashijeet Acharya]

On Tue, Apr 18, 2017 at 10:35 PM, John Snow <address@hidden> wrote:
>
>>
>>     I could be wrong, but that's my hunch.
>>
>>     Maybe you can cache the state of the INFLATE process such that once you
>>     fill the cache with data, we can simply resume the INFLATE procedure
>>     when the guest almost inevitably asks for the next subsequent bytes.
>>
>>     That'd probably be efficient /enough/ in most cases without having to
>>     worry about a metadata cache for zlib blocks or a literal data cache for
>>     inflated data.
>>
>>
>> Yes, I have a similar approach in mind to inflate one sector at a time
>> and save the offset in the compressed stream and treat it as an access
>> point for the next one.
>>
>
> Right, just save whatever zlib library state you need to save and resume
> inflating. Probably the most reasonable way to go for v1. As long as you
> can avoid re-inflating prior data in a chunk when possible this is
> probably good.

Yup, I have started with that. Something you should know is that I had
an IRC discussion with Kevin and he suggested to fix the buffer size
to a max of 2MiB as 512b (which I proposed in my previous response) is
excessively low and will slow down the driver drastically!

Ashijeet