FreeBSD 7.1 tcp problem (syncache)?

Paulo Fragoso paulo at nlink.com.br
Mon Dec 1 12:25:55 PST 2008


On 01/12/2008 12:41, Tom Evans wrote:
> On Mon, 2008-12-01 at 10:53 -0300, Paulo Fragoso wrote:
>   
>> Hi,
>>
>> We was using one machine with FreeBSD 6.4-RELEASE running 
>> apache-worker-2.2.3 + mysql, this server can answer high request from 
>> one client using ab:
>>
>>
>> {client}$ ab -n 2000 -c 1000 http://system_using_6.4-RELEASE
>> ...
>> Benchmarking ***** (be patient)
>> Completed 200 requests
>> Completed 400 requests
>> Completed 600 requests
>> Completed 800 requests
>> Completed 1000 requests
>> Completed 1200 requests
>> Completed 1400 requests
>> Completed 1600 requests
>> Completed 1800 requests
>> Finished 2000 requests
>> ...
>> {client}$
>>
>>
>> Using other hardware whit FreeBSD 7.1-PRERELEASE running 
>> apache-worker-2.2.9_5 + mysql, we have a poor result:
>>
>>
>> {client}$ ab -n 2000 -c 1000 http://system_using_7.1-PRERELEASE
>> ...
>> Test aborted after 10 failures
>>
>> apr_connect(): Invalid argument (22)
>> {client}$
>>
>>
>> Looking for a problem on new server log we found:
>>
>> kernel: TCP: [client]:50197 to [server]:80 tcpflags 0x4<RST>; 
>> syncache_chkrst: Spurious RST without matching syncache entry (possibly 
>> syncookie only), segment ignored
>> kernel: TCP: [client]:53845 to [server]:80 tcpflags 0x4<RST>; 
>> syncache_chkrst: Spurious RST without matching syncache entry (possibly 
>> syncookie only), segment ignored
>> kernel: TCP: [client]:53845 to [server]:80 tcpflags 0x4<RST>; 
>> syncache_chkrst: Spurious RST without matching syncache entry (possibly 
>> syncookie only), segment ignored
>>
>> All sysctl and apache conf are same on both server, is there a tcp 
>> problem with FreeBSD 7.x?
>>
>> Paulo Fragoso.
>>
>>     
>
> Just to rule it out, have you tried testing using a more robust tool
> than ab? ab is generally disliked by the apache devs I've met. Does it
> still fall over using something like siege[1] or flood[2]?
>
> Cheers
>
> Tom
>
> [1] http://www.joedog.org/JoeDog/Siege
> [2] http://httpd.apache.org/test/flood/
>
>
>   

We have tried siege because similar to ab configuration, but we have 
problem to repeat our ab tests:

client$ siege -b -r1000 -c10 http://system_using_7.1-PRERELEASE

HTTP/1.1 200   0.05 secs:    1948 bytes ==> /cgi-bin/path_to_program
HTTP/1.1 200   0.04 secs:    1948 bytes ==> /cgi-bin/path_to_program
HTTP/1.1 200   0.05 secs:    1948 bytes ==> /cgi-bin/path_to_program
Segmentation fault: 11 (core dumped)

same problem is happening trying old url: 
http://system_using_6.4-RELEASE. Have you had some advice?

We are using ab since 2004 to make a historical reference for our tests 
for different hardware and systems.

Why using same hardware to run ab we can test one server running 
6.4-RELEASE but fails to teste 7.1-PRERELEASE? New way to answer request 
in 7.1 can crash ab at another machine? We are suspecting there is a new 
limit in 7.x which not clear for us yet.

Paulo.


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