Re: CPU upgrade caused application slow down

  • From: "zhu chao" <chao_ping@xxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 30 Apr 2004 18:34:37 +0800

Hi, Tim:
    The network traffic of the db server is 15-20Mbit/Second, not MB/Second.
Sorry for the confusion. We are running 100Based LAN between application
server and database server.
    Actully as I said in earlier posts, we upgraded two db servers. The
other one which has cpu upgrade from 12*400MHZ to 8*900MHZ does have less
application response time after upgrade. Average response time for typical
service dropped 30-50 percent.
    But applications running on this server does not. The typical
application response increased for about 5%. This seems strange. We really
cannot explain to boss.

Thanks
Zhu Chao.


----- Original Message ----- 
From: "Tim Gorman" <tim@xxxxxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Friday, April 30, 2004 6:12 PM
Subject: Re: CPU upgrade caused application slow down


> Zhu Chao,
>
> Sustained rates of 15-20 Mbytes/sec is absolute network saturation if
you'r=
> e
> running 100BaseT - don=B9t forget that 100 Mbits/sec is 12.5 Mbytes/sec.
Eve=
> n
> if the network segment closest to the server is GigE, you might have a
> network segment somewhere in the mix running at 100BaseT, perhaps?
>
> Cary's remarks aren't theory, of course.  Making one component of the
stack
> of technology much faster will almost certainly cause a bottleneck in
> another component.  Think of a 10-mile (16 km) roadway where the first 6
> miles (10 km) are expanded to 4 lanes while the remainder is left at 2
> lanes.  That was the situation in my hometown (Evergreen, Colorado) some
> years ago -- guess whether the roadway expansion helped improve traffic
flo=
> w
> or caused massive backups where the lanes reduced from 4 to 2...?
>
> Just some thoughts...
>
> -Tim
>
>
> > 1.. According to Cary Millsap=A1=AFs theory, upgrade CPU *CAN* make
performan=
> ce
> > worse. In his case, SQL*Net was the bottleneck. Our server network
traffi=
> c is
> > only at 15-20Mb/Second. This seems not like the bottleneck, Though from
1=
> 0046
> > trace report, sqlnet wait is the NO.1 wait event, but this is normal for
=
> most
> > applications.  I also tried to change the tnsnames.ora and listener.ora
w=
> ith
> > larger SDU/TDU of 8KB, restarted tuxedo service and oracle listener. And
> > compare the performance data leter. This does not make much difference
fo=
> r
> > application response time.
> >=20
> > 2.. We did some pure simple SQL test. Result in appendix 1. SAME SQL in
> > 1200MHZ CPU does run faster.
> >=20
> > 2.. We write a simple tuxedo service run the same SQL for 1000 times.
> > Everytime the SQL is transferred through SQL*Net and result is fetched
in=
> to
> > host variable. The result still shows that it runs faster on 1200MHZ
CPU.=
>  The
> > average response time in 1200MHZ server is 12.12ms ,and the average
respo=
> nse
> > time in 900mhz server is 14.20ms.
>
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