Am 10.08.2013 18:09, schrieb Yongming Zhao:
>
> 在 2013-8-10，下午11:41，Reindl Harald <h.reindl@thelounge.net> 写道：
>
>>
>> Am 10.08.2013 17:32, schrieb Yongming Zhao:
>>> if your requested URL is expires very often, then you may hit the
>>> read-while-writer performance issue, we have fixed that read-while-writer
>>> in V3.3 that will make it really work.
>>
>> but every 60 seconds is not that often in case of a apache-benchmark
>> it's a simple calculation how many cache-hits you can have within
>> this 60 seconds by 200 parallel requests of the same URL
>>
>
> we care of the performance, but your case is mixing with the feature
> of read-while-writer, if you get to know that read-while-writer may
> affect your performance result, that will help us compare the result,
> in the better understanding.
CONFIG proxy.config.cache.enable_read_while_writer INT 0
does not change anything
>>> please compare the Origin Side traffic during the test
>>
>> the origin is 127.0.0.1:80 but 6 prefork-processes
>> while "ab -c 200" is running indicates pretty clear
>> that all the work is ATS
>>
>> [root@testserver:~]$ ps aux | grep httpd | wc -l
>> 6
>
> I mean, how many requests you get from the origin side during your testing, or hit ratio
*none* which is pretty clear in case of a preforking-httpd
StartServers 3
MinSpareServers 3
MaxSpareServers 5
so the 6 httpd-processes are the master-process and 5 idle workers
>>> and you'd better try the compare without expire issue, to make sure we have
>>> not make critical regression there.
>>
>> no - if this is a problem now *it is* a critical regression
>>
>> the only reason trafficserver exists in our infrastructure
>> is to buffer high-traffic sites with a lot of images and
>> hold back the image-count multiplied with users requests
>> from teh preforking-apache
>
> if you want to enable read while writer, that means you care of the origin side traffic,
> and you may need to pay for the performance drop in speed(response time) on the proxy,
> when that url is getting fetched from the origin
please stop to insist in "read while writer"
* disable it does not change anything
* 100000 requests with 200 parallel are done within the 60 seconds expire
* hence we speak about *one* single URL, only *one* object requested and cached
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