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From Reindl Harald <h.rei...@thelounge.net>
Subject Re: 3.3.5: performance regression?
Date Sat, 10 Aug 2013 15:41:47 GMT

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

> 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

> 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

> 在 2013-8-10,下午11:14,Reindl Harald <h.reindl@thelounge.net> 写道:
> 
>>
>> Am 10.08.2013 16:46, schrieb Leif Hedstrom:
>>> On Aug 10, 2013, at 7:21 AM, Reindl Harald <h.reindl@thelounge.net> wrote:
>>>
>>>> has anybody compared 3.2 / 3.3 in performance?
>>>>
>>>> ab -c 200 -n 100000 http://<url>/rte/upload/logo.gif while "logo.gif"
is
>>>> 643 bytes small and currently httpd without Trafficserver in front has
>>>> nearly the same perfomrance with even lower CPU
>>>
>>> I haven't seen this behavior. Are you positive the 3.3.5 results are cache hits
? And if so, that they become RAM cache hits? Just trying to get some ideas here … :)
>>
>> i hope so, if not that would be a bug
>>
>> [root@testserver:~]$ curl --head http://rhsoft.testserver/rte/upload/logo.gif
>> HTTP/1.1 200 OK
>> Date: Sat, 10 Aug 2013 15:09:31 GMT
>> Last-Modified: Tue, 11 Apr 2006 10:40:40 GMT
>> ETag: "283-411255ab33a00"
>> Accept-Ranges: bytes
>> Content-Length: 643
>> Cache-Control: max-age=60
>> Expires: Sat, 10 Aug 2013 15:10:31 GMT
>> X-Content-Type-Options: nosniff
>> Connection: close
>> Content-Type: image/gif
>>
>> on the origin mod_expires is in action to set 60 seconds
>> cache for images because in our case we have 100% dynamic
>> pages and the job of ATS is only hold back the image/css/js
>> requests from the preforking apache and offer KeepAlive
>>
>> the 60 seconds are reflected in the curl-repsonse abvove
>> which comes from the origin (127.0.0.1:80)
>>
>> <IfModule mod_expires.c>
>> ExpiresActive On
>> ExpiresByType image/jpeg A60
>> ExpiresByType image/jpg A60
>> ExpiresByType image/gif A60
>> ExpiresByType image/png A60
>> ExpiresByType text/css A60
>> ExpiresByType text/html A60
>> ExpiresByType text/javascript A60
>> ExpiresByType text/comma-separated-values A60
>> ExpiresByType text/tab-separated-values A60
>> ExpiresByType application/javascript A60
>> ExpiresByType application/x-javascript A60
>> ExpiresByType application/xhtml+xml A60
>> ExpiresByType application/xml A60
>> <IfModule/>
>>
>>
>>> Reclaimable freelist would not have these sort of performance discrepancies
>>
>> yes, and it should not matter in a (ok small) cache with only a handful of objects


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