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From Bill Stoddard <b...@wstoddard.com>
Subject Re: mod_cache performance
Date Tue, 03 Aug 2004 14:48:55 GMT
Bill Stoddard wrote:

> Justin Erenkrantz wrote:
> 
>> --On Monday, August 2, 2004 2:49 PM -0400 Bill Stoddard 
>> <bill@wstoddard.com> wrote:
>>
>>> To get mod_cache/mod_mem_cache (I know little or nothing about
>>> mod_disk_cache) really performing competatively against best-of-breed 
>>> caches
>>> will require bypassing output filters (and prebuilding headers) and 
>>> possibly
>>
>>
>>
>> Here's some comparative numbers to chew on.
>>
>> One client and one server on 100Mbps network (cheapy 100Base-T switch);
>> 50 simulated users hitting 7 URLs 100 times with flood (35,000 requests).
>>
>> mod_disk_cache: Requests: 35000 Time: 40.91 Req/Sec: 856.78
>> mod_mem_cache:  Requests: 35000 Time: 54.90 Req/Sec: 637.81
>> no cache:       Requests: 35000 Time: 54.86 Req/Sec: 638.81
>> squid:          Requests: 35000 Time: 105.35 Req/Sec: 332.25
>>
>> mod_disk_cache completely filled out the network at ~50% CPU usage.
>>    [Can't push through more than ~8MB/sec (~64Mb/sec) without GigE.]
>> mod_mem_cache filled up the CPU but not the network
>>    [Poor scaling characteristics.  It goes to 100% CPU with just 5 
>> users!]
> 
> 
> mod_mem_cache is broken 
Or mistuned?
Here are the defaults for the mem_cache directives:

MCacheSize               ~100 MB
MCacheMaxObjectCount     1009
MCacheMinObjectSize      0 (bytes)
MCacheMaxObjectSize      10000 (bytes)
MCacheRemovalAlgorithm    GDSF
MCacheMaxStreamingBuffer 100000 (bytes)

I have no idea if the urls ending in / are being served at all by mod_mem_cache. Wouldn;t
suprise me if tehre 
is a bug there.

Bill

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