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From Brian Akins <bak...@web.turner.com>
Subject Re: mod_cache performance
Date Tue, 03 Aug 2004 12:49:32 GMT
Eli Marmor wrote:

>Graham Leggett wrote:
>  
>
>>Brian Akins wrote:
>>
>>    
>>
>>>On an OS that supports sendfile, a disk based cache will almost always
>>>bury a memory based one.
>>>      
>>>
>>Quite probably. But on a system without a disk, chances are it won't. :(
>>    
>>
>
>It will.
>Unless mod_disk_cache + ram-disk + sendfile doesn't outperform
>mod_mem_cache.
>
>  
>
This setup performs quite nicely on Linux.

The big hits for mem cache are:

The cache is not shared between processes, so you use alot more memory 
and have a lot less "hits."

You have to copy data from user to kernel, which can be a huge hit.


Even without sendfile, mmap is generally faster than mem cache.

-- 
Brian Akins
Senior Systems Engineer
CNN Internet Technologies


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