Monday, December 6, 2010

How to minimize CPU utilization when using Dynamips/GNS3 (idlepc + idlemax)

This is my experiment in minimizing the CPU usage when working on GNS3/Dynamips. On this experiment I have use the Internetwork Expert Topology (INE) Version 5 which has 13 routers and uses 3725 IOS images.
 
If you need the topology just visit INE Website.
 
 
 
For this experiment I already obtain the ideal idlepc of the IOS version the topology uses.
 
This is the what inside the .NET file.
 
autostart = False
[localhost:7202]
workingdir = C:\Gns3\workingDIR
udp = 12000
[[3725]]
image = C:\Gns3\IOS\c3725-adventerprisek9-mz.124-15.T5.bin
ram = 128
ghostios = True
idlepc = 0x60bed2e0
 
 
 
On the above .NET file I'm only using the idlepc to minimize the CPU usage. If you check the Task Manager we are using about 30% Utilization of the CPU for only the initial configuration of the INE Topology.
 
 
Now  this is the .NET file which the idlepc+idlemax are use.
autostart = False
[localhost:7202]
workingdir = C:\Gns3\workingDIR
udp = 12000
[[3725]]
image = C:\Gns3\IOS\c3725-adventerprisek9-mz.124-15.T5.bin
ram = 128
ghostios = True
idlepc = 0x60bed2e0
idlemax = 100
 
Wow.... The CPU utilization is only 3% which is 1/10th when using only the idlepc setting for the .NET file.
 
This just show that the combination of idlepc+idlemax is very useful when using GNS3/Dynamips.
 
PC Spec:
- Core i5-650
- 4GB Mem
- WinXP SP3

13 comments:

  1. It's very usefull, this should be in doc in GNS3. I was close to buy new laptop, but idlemax helped me. Thank you.

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  2. hey Brother could u pls tell me how to set idlemax
    in Gns3 i search but didn't get any option pls let me know

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  3. Hey Praveen,

    Just look at the .net file created by the GNS3 and add the idlemax line.

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  4. Hi..

    i have just installed the gns3 and when i started a router my cpu usage reached to 100%, as above mentioned comments we need to change ildemax in .net file but where i can find this file.??

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  5. Can some one help me out? i tried to follow this yet my CPU spiked 100%. below is the idlemax value i added yet no difference.

    autostart = False
    [127.0.0.1:7200]
    workingdir = C:\DOCUME~1\Karmesh\LOCALS~1\Temp
    udp = 10000
    [[3640]]
    image = G:\LABS\IOS\c3640-ik9s-mz.124-25b.bin
    idlepc = 0x60696f6c
    idlemax = 100
    sparsemem = True

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  6. @saha,

    idlepc is IOS specific.. to get the proper idlepc 1.)Load a single router on the GNS3
    2.)Power it up
    3.)Console to the router
    4.)get into privilege mode
    5.)right click into the router and select idlepc calculation
    6.)choose the value with *.

    i hope this could help..

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  7. Thanks for this. Dropped my CPU 70%!

    Thanks!

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  8. Worked on Ubuntu 10.10 by the way

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  9. Thanks man. I was almost going to buy a new labtop too. Idlemax makes perfect. you're genious

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  10. good one
    ....people like you save the world

    ReplyDelete
    Replies
    1. There is now a much better that the Dynamips that the IOU but the only problem it is only for Cisco internal use.. hopefully they could provide one for FREE....

      some say you could run the whole INE topology on an ATOM machine..

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