Dummy network device

Dummy network device

[Richard W. Knight]

Hello,

After I upgraded to 2.6.3 from 2.4.20 I discovered that I can only get 1 
dummy device. I need to be able to load 3 dummy network devices. 
Scouring the kernel archives, it looks like this can be accomplished 
through MODULE_PARAMS, but I can find no information on the 
module_params are or how to use them. I have dummy built as a module and 
it does load at startup as dummy0. How do I get dummy1 and dummy2?

In answering this message, please CC me.

Thanks for your help,
Rick Knight
(rick@rlknight.com)

Dummy network device

[Rick Knight]

> Hello,
>
> After I upgraded to 2.6.3 from 2.4.20 I discovered that I can only get 
> 1 dummy device. I need to be able to load 3 dummy network devices. 
> Scouring the kernel archives, it looks like this can be accomplished 
> through MODULE_PARAMS, but I can find no information on the 
> module_params are or how to use them. I have dummy built as a module 
> and it does load at startup as dummy0. How do I get dummy1 and dummy2?
>
> In answering this message, please CC me.
>
> Thanks for your help,
> Rick Knight
> (rick@rlknight.com)


Never mind,

I found the answer. From the archive. Decided to look at dummy.c and 
numdummies=1, changed it to numdummies=3 and rebuilt that module. Works 
like a charm.

Question/Suggestion, couldn't this be made an option at configuration? 
Kind of like number_of_ptys=256.

Please CC  me with any response.

Thanks,
Rick Knight
(rick@rlknight.com)

Re: Dummy network device

[Randy.Dunlap]

On Tue, 09 Mar 2004 15:11:48 -0800 Rick Knight wrote:

| > Hello,
| >
| > After I upgraded to 2.6.3 from 2.4.20 I discovered that I can only get 
| > 1 dummy device. I need to be able to load 3 dummy network devices. 
| > Scouring the kernel archives, it looks like this can be accomplished 
| > through MODULE_PARAMS, but I can find no information on the 
| > module_params are or how to use them. I have dummy built as a module 
| > and it does load at startup as dummy0. How do I get dummy1 and dummy2?
| >
| > In answering this message, please CC me.
| >
| > Thanks for your help,
| > Rick Knight
| > (rick@rlknight.com)
| 
| 
| Never mind,
| 
| I found the answer. From the archive. Decided to look at dummy.c and 
| numdummies=1, changed it to numdummies=3 and rebuilt that module. Works 
| like a charm.
| 
| Question/Suggestion, couldn't this be made an option at configuration? 
| Kind of like number_of_ptys=256.

It's supposed to be changeable at module load time, without
rebuilding it.  Try this e.g.:

modprobe dummy numdummies=4

--
~Randy

Re: Dummy network device

[David S. Miller]

On Tue, 09 Mar 2004 15:11:48 -0800
Rick Knight <rick@rlknight.com> wrote:

> I found the answer. From the archive. Decided to look at dummy.c and 
> numdummies=1, changed it to numdummies=3 and rebuilt that module. Works 
> like a charm.
> 
> Question/Suggestion, couldn't this be made an option at configuration? 
> Kind of like number_of_ptys=256.

Specify "numdummies=3" on the module load command line.

Re: Dummy network device

[Rick Knight]

David S. Miller wrote:

>On Tue, 09 Mar 2004 15:11:48 -0800
>Rick Knight <rick@rlknight.com> wrote:
>
>  
>
>>I found the answer. From the archive. Decided to look at dummy.c and 
>>numdummies=1, changed it to numdummies=3 and rebuilt that module. Works 
>>like a charm.
>>
>>Question/Suggestion, couldn't this be made an option at configuration? 
>>Kind of like number_of_ptys=256.
>>    
>>
>
>Specify "numdummies=3" on the module load command line.
>  
>
>It's supposed to be changeable at module load time, without
>rebuilding it.  Try this e.g.:
>
>modprobe dummy numdummies=4
>
>--
>~Randy
>  
>
Randy, David,

Thanks for the replies.

I did try 'modprobe dummy numdummies=3', however, I didn't quote 
numdummies=3. Are the quote required? Is there a modprobe.conf option? 
Probably "options dummy "numdummies=3".

Thanks,
Rick Knight
(rick@rlknight.com)

Re: Dummy network device

[Randy.Dunlap]

| From: Rick Knight
| 
| David S. Miller wrote:
| 
| >On Tue, 09 Mar 2004 15:11:48 -0800
| >Rick Knight <rick@rlknight.com> wrote:
| >
| >  
| >
| >>I found the answer. From the archive. Decided to look at dummy.c and 
| >>numdummies=1, changed it to numdummies=3 and rebuilt that module. Works 
| >>like a charm.
| >>
| >>Question/Suggestion, couldn't this be made an option at configuration? 
| >>Kind of like number_of_ptys=256.
| >>    
| >>
| >
| >Specify "numdummies=3" on the module load command line.
| >  
| >
| >It's supposed to be changeable at module load time, without
| >rebuilding it.  Try this e.g.:
| >
| >modprobe dummy numdummies=4
| >
| >--
| >~Randy
| >  
| >
| Randy, David,
| 
| Thanks for the replies.
| 
| I did try 'modprobe dummy numdummies=3', however, I didn't quote 
| numdummies=3. Are the quote required? Is there a modprobe.conf option? 
| Probably "options dummy "numdummies=3".

No, the quotes are not required.  This works for me:
modprobe dummy numdummies=3

Using /etc/modprobe.conf also works, as you suggested, but without
the quotation marks:
options dummy numdummies=3

Either way shows this in /proc/net/dev:

dummy0:       0       0    0    0    0     0          0         0        0
 0    0    0    0     0       0          0
dummy1:       0       0    0    0    0     0          0         0        0
 0    0    0    0     0       0          0
dummy2:       0       0    0    0    0     0          0         0        0
 0    0    0    0     0       0          0


HTH.
--
~Randy

Re: Dummy network device

[Rick Knight]

Randy.Dunlap wrote:

>| From: Rick Knight
>| 
>| David S. Miller wrote:
>| 
>| >On Tue, 09 Mar 2004 15:11:48 -0800
>| >Rick Knight <rick@rlknight.com> wrote:
>| >
>| >  
>| >
>| >>I found the answer. From the archive. Decided to look at dummy.c and 
>| >>numdummies=1, changed it to numdummies=3 and rebuilt that module. Works 
>| >>like a charm.
>| >>
>| >>Question/Suggestion, couldn't this be made an option at configuration? 
>| >>Kind of like number_of_ptys=256.
>| >>    
>| >>
>| >
>| >Specify "numdummies=3" on the module load command line.
>| >  
>| >
>| >It's supposed to be changeable at module load time, without
>| >rebuilding it.  Try this e.g.:
>| >
>| >modprobe dummy numdummies=4
>| >
>| >--
>| >~Randy
>| >  
>| >
>| Randy, David,
>| 
>| Thanks for the replies.
>| 
>| I did try 'modprobe dummy numdummies=3', however, I didn't quote 
>| numdummies=3. Are the quote required? Is there a modprobe.conf option? 
>| Probably "options dummy "numdummies=3".
>
>No, the quotes are not required.  This works for me:
>modprobe dummy numdummies=3
>
>Using /etc/modprobe.conf also works, as you suggested, but without
>the quotation marks:
>options dummy numdummies=3
>
>Either way shows this in /proc/net/dev:
>
>dummy0:       0       0    0    0    0     0          0         0        0
> 0    0    0    0     0       0          0
>dummy1:       0       0    0    0    0     0          0         0        0
> 0    0    0    0     0       0          0
>dummy2:       0       0    0    0    0     0          0         0        0
> 0    0    0    0     0       0          0
>
>
>HTH.
>--
>~Randy
>  
>
Randy,

I did try 'modprobe dummy numdummies=3' and I didn't work. I got an 
error and the following showed up in /var/log/messages...

Mar  9 14:42:33 l43w2k021 modprobe: FATAL: Error inserting dummy 
(/lib/modules/2.6.3/kernel/drivers/net/dummy.ko): Unknown symbol in 
module, or unknown parameter (see dmesg)

Now it works and I get no error message. I tried numdummies= on another 
similarly configured machine and it worked first time. So maybe the 
error message above was caused by a typo when I tried it the first time

Anyway, numdummies= does work as you said.

Thanks,
Rick Knight
(rick@rlknight.com)