[httperf] Re: Connection rate is very low

Vikash Kumar vikash.kumar at oneconvergence.com
Tue Oct 23 07:50:24 PDT 2012


Hi all,

   I was able to achieve 7000 conn/sec. But this is also very low in
compare to 27K conn/sec may be I need to increase server m/c's.

   One error that I observed was TCP SYN flooding message in dmesg. Victor
suggested to make *tcp_syncookies=0.* After doing that my connection rate
also got decreased and I got some  message in my dmesg:

  process `sysctl' is using deprecated sysctl (syscall)
net.ipv6.neigh.default.retrans_time; Use
net.ipv6.neigh.default.retrans_time_ms instead.
  TCP: Possible SYN flooding on port 80. Dropping request.  Check SNMP
counters.

  This clearly mean that disabling syn_cookies is not solution, may be I am
wrong or may be their is other way out.

  Is their any way to mitigate this "Possible SYN flooding "? Any detail
description will be

  Other error that I got in client side is:

   httperf : connection failed with error 98

  After doing grep for error 98. I got the macro as "Address already in
Use".

  How to mitigate that error? I am using Ubuntu 10.04

Regards,
Vikash



On Tue, Oct 23, 2012 at 3:22 PM, Vikash Kumar <
vikash.kumar at oneconvergence.com> wrote:

> But Victor that will lead to drop more legitimate connections.
>
> Thnx
>
>
> On Tue, Oct 23, 2012 at 2:19 PM, Vikash Kumar <
> vikash.kumar at oneconvergence.com> wrote:
>
>> Thnx Victor.
>>
>> On Tue, Oct 23, 2012 at 12:24 PM, Gattegno, Victor (CPR&Q GCC - ISS/SW
>> Tower) <victor_gattegno at hp.com> wrote:
>>
>>>  Hi Vikash* *****
>>>
>>> ** **
>>>
>>> **Ø  **What can be done to stoop this message?****
>>>
>>> ** **
>>>
>>> You could do this:****
>>>
>>> ** **
>>>
>>> *# echo 0 > /proc/sys/net/ipv4/tcp_syncookies*****
>>>
>>> ** **
>>>
>>> Or, if you want it permanent (after reboot), set:
>>> net.ipv4.tcp_syncookies = 0 in /etc/sysctl.conf****
>>>
>>> ** **
>>>
>>> Rgds,****
>>>
>>> Victor****
>>>
>>> ** **
>>>
>>> *From:* httperf-bounces at linux.hpl.hp.com [mailto:
>>> httperf-bounces at linux.hpl.hp.com] *On Behalf Of *Vikash Kumar
>>> *Sent:* lundi 22 octobre 2012 13:58
>>> *To:* httperf at linux.hpl.hp.com
>>>
>>> *Subject:* [httperf] Re: Connection rate is very low****
>>>
>>>  ** **
>>>
>>>   I am also getting TCP SYN flooding msg in dmesg of *Haproxy host m/c*:
>>> ****
>>>
>>> ** **
>>>
>>>   [ 2965.742025] possible SYN flooding on port 80. Sending cookies.****
>>>
>>> ** **
>>>
>>>   Command   *cat /proc/sys/net/ipv4/tcp_syncookies is set to 1.* ****
>>>
>>> ** **
>>>
>>> *   *What can be done to stoop this message?****
>>>
>>> ** **
>>>
>>> Regards,****
>>>
>>> Vikash* *****
>>>
>>> ** **
>>>
>>> _______________________________________________
>>> httperf mailing list
>>> httperf at linux.hpl.hp.com
>>> http://www.hpl.hp.com/hosted/linux/mail-archives/httperf/
>>>
>>
>>
>
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