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From Bill Stoddard <>
Subject Re: [PATCH] mod_cache fixes: #8
Date Mon, 02 Aug 2004 18:49:22 GMT
Justin Erenkrantz wrote:
mod_cache isn't doing anything stupid or damaging
> performance-wise, I'd like to start being more aggressive about what we 
> can cache.  From my perspective, these patches I've posted (and started 
> to commit) are just the beginning of trying to get mod_cache on more 
> solid ground both performance and RFC-wise.  And, that needs to happen 
> before mod_cache can even get out of experimental...  -- justin
To get mod_cache/mod_mem_cache (I know little or nothing about mod_disk_cache) really performing
against best-of-breed caches will require bypassing output filters (and prebuilding headers)
and possibly 
bypassing or at least reworking input filters. And the prebuilt headers will need to be properly
aligned in 
memory. You remember the patch I posted to the list, gee, maybe up to 2 years ago now to reimplement
aspects of how data was read into input filters? Dipping into the input stream to read one
line at a time 
turns out to be a fairly significant bottleneck serving cached content. That patch improved
servibg cached content by 5 maybe 10% if I recall correctly.

I also seem to recall mod_cache/mod_mem_cache making a couple of gratuitous calls to apr_time()
which can be 
rather expensive on some platforms.  Maybe that has changed since last time i looked at it.


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