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Posted to dev@trafficserver.apache.org by Bryan Call <bc...@apache.org> on 2012/06/19 22:58:15 UTC
Comparison of ATS 3.1.3 and 3.1.4
This is a simple write up I did comparing the response times for ATS 3.1.3 and 3.1.4 in one colo. The response times in the squid logs dropped a lot between these two versions of the code.
-Bryan
Re: Comparison of ATS 3.1.3 and 3.1.4
Posted by Bryan Call <bc...@yahoo-inc.com>.
It had to do with the listen queue being set low on one of the servers, the one running 3.1.3. We noticed the problem when we upgraded all the servers to 3.2.0 and still the server was "slower".
somaxconn was not being set to 16,384 and was at the default 128. We believe there is a weird interaction with overflowing the listen queue, having syncookies on, and tcp defer accept. What we think is happening is connections that have been syncookied come back and bypass the tcp defer accept. Since the timer for the first request in ATS starts when the connection is accepted this increases the response time in the stats and logs.
We were not able to measure any response differences from the client side and only saw the time differences in the stats and logs.
-Bryan
On Jun 21, 2012, at 7:09 AM, John Plevyak wrote:
> Very interesting. Any idea as to the cause?
>
> john
>
> On Tue, Jun 19, 2012 at 2:15 PM, Bryan Call <bc...@yahoo-inc.com> wrote:
>
>> Since attachments are stripped out:
>>
>> http://people.apache.org/~bcall/3.1.3_vs_3.1.4.pdf
>>
>> -Bryan
>>
>> On Jun 19, 2012, at 1:58 PM, Bryan Call wrote:
>>
>>> This is a simple write up I did comparing the response times for ATS
>> 3.1.3 and 3.1.4 in one colo. The response times in the squid logs dropped
>> a lot between these two versions of the code.
>>>
>>> -Bryan
>>>
>>
>>
Re: Comparison of ATS 3.1.3 and 3.1.4
Posted by John Plevyak <jp...@acm.org>.
Very interesting. Any idea as to the cause?
john
On Tue, Jun 19, 2012 at 2:15 PM, Bryan Call <bc...@yahoo-inc.com> wrote:
> Since attachments are stripped out:
>
> http://people.apache.org/~bcall/3.1.3_vs_3.1.4.pdf
>
> -Bryan
>
> On Jun 19, 2012, at 1:58 PM, Bryan Call wrote:
>
> > This is a simple write up I did comparing the response times for ATS
> 3.1.3 and 3.1.4 in one colo. The response times in the squid logs dropped
> a lot between these two versions of the code.
> >
> > -Bryan
> >
>
>
Re: Comparison of ATS 3.1.3 and 3.1.4
Posted by Bryan Call <bc...@yahoo-inc.com>.
Since attachments are stripped out:
http://people.apache.org/~bcall/3.1.3_vs_3.1.4.pdf
-Bryan
On Jun 19, 2012, at 1:58 PM, Bryan Call wrote:
> This is a simple write up I did comparing the response times for ATS 3.1.3 and 3.1.4 in one colo. The response times in the squid logs dropped a lot between these two versions of the code.
>
> -Bryan
>