08-05-2008 07:07 AM - edited 03-03-2019 11:01 PM
Rapid Explanation:
I have 96% of CPU Interrupt utilization with only 96kpps.
Need I replace my routers with more powerful router ?
Long Explanation:
My test bench is compose by 2 routers (c7200p-advsecurityk9-mz.124-15.T4.bin) connected together with ATM PA-A6-OC3-MM.
I'm using a Smartbits tester connected by 3 Fastethernet to each routeur. I send a total of 96kpps (trame size: 312 bytes) over its 3 Fastethernet interface connected to the first router, and receiving them on its other 3 Fastethernet connected to the second router.
With a light configuration (only one static route and interface IP addressing), I have this result:
Result for 96kpps (half in on direction, and half in the other direction):
Total CPU Utilization: 41%
Process Utilization: 1%
Interrupt Utilization: 40%
I have already 40% of Interrupt Utilization.
Now I use my complete configuration file: service-policy input on 2 Fastethernet, and service-policy output on ATM, OSPF for routing between, all interface Policy and CEF switched.
Result for 96kpps:
Total CPU Utilization: 94%
Process Utilization: 0%
Interrupt Utilization: 94%
=> Great, all packets are CEF switched (service policy managed by hardware) and no packet dropped
But, I'm using a 7204 with NPE-G2 that theoretically support 2Mppsâ¦
How to explain that I'm already obtain 94% of Interrupt Utilization with only 96kpps ?
Thanks
Solved! Go to Solution.
08-07-2008 06:53 AM
i guess u have lot of service poilices working no your router. Remember, the source based routing is one of the major cpu/memory hogs. Try to eliminate some of the policies with tradiontal traffic engineering and paste the results.
08-05-2008 11:36 AM
Hi Gugus,
from what I've learned on the c-nsp mailing list the CPU stats are not linear with the load. This meets with my results here.
Taking in bidirectional packetflows:
100kpps = 49%
200kpps = 60%
400kpps = 78%
600kpps = 97%
Cheers, /Rene
08-07-2008 06:53 AM
i guess u have lot of service poilices working no your router. Remember, the source based routing is one of the major cpu/memory hogs. Try to eliminate some of the policies with tradiontal traffic engineering and paste the results.
08-07-2008 07:43 AM
I've use the Smartbits tester for other performance test on the NPE-G2 for trying to found what excatlly cause this low perf.
And here are the resuts for the first test on a single Cisco 7204 using the two Gigabit Ethernet port.
The smartbits send a bidirectionnal flow of 2.8Mpps (UDP packet of 64bytes size) across the router.
With the default configuration, the router can forward at 1,72Mpps... (CPU was at 99%)
Now I test the service-policy impact by sending a unidirectionnal flow (UDP packet of 64bytes size, dscp 0).
- Light service policy output (match dscp cs6 and bandwitdh percent 100 on this matched traffic). The generated traffic doesn't match
: forwanding rate is 940Kpps
- My customized Service policy output. The generated traffic doesn't match : forwanding rate is 413Kpps
- Light service policy input (extended ACL witch match dscp cs6 and remark dscp to af32). The generated traffic doesn't match: forwanding rate is 750Kpps
- Light Service policy input light (standard ACL standard which match non existant host and remank dscp to af32). The generated traffic doesn't match: forwanding rate is 788Kpps
- Light service policy input (standard ACL standard which match any and remank dscp to af32). The generated traffic match, forwanding rate is 740 Kpps
- My light Service policy input. The generated traffic doesn't match, forwanding rate is 780Kpps
- My light Service policy input AND my customized output: forwanding rate is 325Kpps.
Impact of using Service policy:
=> The router performance is half with a single light service policy... Enabling service policy have a big impact!
With my customized configuration, I reduce the performance with a factor of 5.
This mean that with my configuration, I can manage about 160kpps in production (for limiting my CPU to reach 70%).
...But 160kpps mean about 400Mb/s Ethernet (340 bytes size packet) and I want to use only an OC3 ATM interface, then it should be OK.
I continue my tests and use now two routers 7204 connected by ATM OC3 (155Mb/s ATM).
Performance drop to 96kpps (about 280 Mb/s ATM bidirectionnal)... The use of an ATM interface consume a lot of ressource to the NPE-G2.
For having an useable throughtput on the field, with my ATM and QoS configuration, I need to use only 70Kpps (CPU at 70%).
If I remove my service policy output and input then I can use it at 101kpps (about 297Mb/s ATM bidirectionnal) this is the maximum of this link with a CPU at 70%.
These tests permit me to found that the NPE-G2 is still too light for using "normal" QoS service-policy on an ATM OC3 interface.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide