RE: N/w Bottleneck Check using tnsping under Tran. Load ... Basic Qs

Hi,  

It takes at most ~1.475MB of data in your servers network stack send buffers to cause a 118ms jump in reply time ( 100Mbit / 8 * 0.118 = 1.475 MB ).  

In practice this number is probably lower.  

You can run netstat in HP-UX couple of times and calculate how many bytes worth of TCP packets are sent out:  

    netstat -f inet -p tcp  

And this command (depending on your OS version) should show a statistic called "outbound queue length". If this is constantly high (tens of thousands packets I'd say) then there's a network bandwidth issue, also if "outbound discards" is non-zero then there's definitely some problem in network transmission.  

    /usr/sbin/lanadmin -g mibstats  

Solutions? IF the commands above show a bandwidth bottleneck (high utilization and long outbound queues) then get higher bandwidth network interfaces or multiple network interfaces. Otherwise the problem is somewhere else.  

One specific case may be that the NIC interrupt handler is bound to a specific CPU but can't get onto CPU enough due an Oracle process running there with the SCHED_NOAGE bit which keeps the process on CPU until it voluntarily yields it. But that's just a guess, I suspect that your issue is just in the low-throughput NIC.  

--
Regards,
Tanel Poder
http://blog.tanelpoder.com <http://blog.tanelpoder.com/> 

 




  _____  


From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of VIVEK_SHARMA
Sent: Saturday, May 31, 2008 12:35
To: Tanel Poder; oracle-l_at_freelists.org
Subject: RE: N/w Bottleneck Check using tnsping under Tran. Load ... Basic
Qs



YES Tanel. ping is also giving a similar increased Timing of about 118 ms
under Peak Load.

 

Cheers

 




  _____  



From: Tanel Poder [mailto:tanel.poder.003_at_mail.ee] 
Sent: Saturday, May 31, 2008 8:53 AM



Does plain Unix ping also experience similar latency increase?

 

 




  _____  



From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of VIVEK_SHARMA
Sent: Saturday, May 31, 2008 03:52
To: Tanel Poder; oracle-l_at_freelists.org



Thanks V much Tanel for responding, as always.

CPU Usage of BOTH DB & APP Servers is about 30 % only at Peak Load when
tnsping is giving a Timing of 118 ms. Hence do Not expect any CPU runqueue.

 

 


--
http://www.freelists.org/webpage/oracle-l