Re: lookup caching

[Raghavendra G <raghavendra@xxxxxxxxxxx>]

On Thu, Apr 8, 2010 at 1:21 AM, Olivier Le Cam <Olivier.LeCam@xxxxxxxxxxxxxxxxxxxxx> wrote:

Olivier Le Cam wrote:

Hi -

Apologize for my insistance, but would it be possible to help on the stats caching? This seriously decreases performances with small files readings!

I am volunteer to try to deal with stats caching by myself but I would appreciate some guidance in order to know where I could interact in the code for.

Well, as far as I understand the problem is rather that folders on the path of the targeted file are not cached at all by io-cache.

Did you mean caching dentries, when you said "caching directories"? io-cache only caches file data. Also note that it is not a translator which does metadata (stats) caching.

This is why accessing a file makes (quite a lot) network traffic and can introduce bottlenecks because each folder is stated on the servers before delivering the file, even if that file is indeed cached by io-cache.

io-cache only sends stat on the file being read not to all of its parent directories. I am not getting the reason you are concerned with too many stat calls. io-cache (during read and when file is cached) only sends a single stat call and that too if "cache-timeout" number of seconds have been elapsed since last validation.

I'm still trying to figure out how I can get this cached as well and will appreciate any pointers.

Thanks and best regards,
--
Olivier

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-- 
Raghavendra G