Re: [squid-users] PC133 SDRAM Fast Enough; StoreEntry

On Tue, 13 Apr 2004, Matt wrote:

> Is PC133 SDRAM fast enough or must you use DDR? What will the performance
> difference be between the two?

So far I have not measured any significant difference..

> I keep thinking that with ~40gig in the cache it must cycle through all the
> RAM to see if it has a copy of the requested object.

Ofcourse not. Very few memory accesses is required to find the correct
StoreEntry. Internally Squid is using a large hash table.

> To go into this further. Squid keeps a 72 byte MD5 StoreEntry for every
> object in the cache. So with ~7 million objects in the cache does Squid
> need to search on average half of 512M of RAM to see if a given object is in
> the cache? How does this work?

By using a hash table based on the MD5 of the request URL.

The size of this hash table is based on the size of your cache. See
cache.log on start up for detail on your setup (Store Buckets). Also see
the store_avg_object_size and objectsPerBucket directives.

Regards
Henrik
Received on Wed Apr 14 2004 - 01:45:31 MDT