[linux-audio-user] Re: Current merrits of tmpfs with Jack

Russell Hanaghan hanaghan at starband.net
Sat Jan 7 01:56:04 EST 2006


Russell Hanaghan wrote:

> Russell Hanaghan wrote:
>
>> Paul Davis wrote:
>>
>>> On Fri, 2005-12-23 at 15:31 -0800, Kjetil S. Matheussen wrote:
>>>  
>>>
>>>> Lee Revell:
>>>>  
>>>>
>>>>>>>>> Jack then needs to be compiled as such right? That is, 
>>>>>>>>> specifically to
>>>>>>>>> use /dev/shm as a tmpfs?
>>>>>>>>>             
>>>>>>>>
>>>>>>>>
>>>>>>>> You know there's actually no good reason this has to be a 
>>>>>>>> compile time
>>>>>>>> setting.  It would be trivial to modify JACK to set this at 
>>>>>>>> runtime.
>>>>>>>>           
>>>>>>>
>>>>>>>
>>>>>>> how would a client know where to find the server sockets?
>>>>>>>
>>>>>>>         
>>>>>>
>>>>>>
>>>>>> By having a file called something like /tmp/jack_server_sockets_path
>>>>>> containing info about where the server sockets are?
>>>>>>
>>>>>>       
>>>>>
>>>>>
>>>>> $HOME/.jack_server_sockets_path?
>>>>>     
>>>>
>>>>
>>>> Yes, either $HOME/.jack_server_sockets_path_<hostname>
>>>> or /tmp/jack_server_sockets_path_<username>
>>>>   
>>>
>>>
>>>
>>> this looks to me like a 50% solution. it solves part of the problem
>>> (allowing the location of the actual sockets/fifos to be determined at
>>> runtime) by substituting another compile-time-only path instead. i see
>>> the attraction, i am just not sure its the best solution.
>>>
>>> --p
>>>
>>>
>>>
>>>  
>>>
>> So the first solution is the most solid; compile jack to utilize 
>> /dev/shm?
>>
>> Unless there is some trade off or sacrifice when doing so to either 
>> the systems stability and performance, or to jackits stability / 
>> performance, I don't see this as a major problem.
>>
>> thanks
>> R~
>
Ok...so no-one answered which tells me RTFM~ :) So I am reading the 
sorceforge jack site pages....And now Im confused even more.

<snip>


      Prerequisites

    * 2.4, 2.5 or 2.6 series kernel with tmpfs turned on (CONFIG_TMPFS)
    * Shared memory file system mounted on /dev/shm. add the following
      to /etc/fstab to get it mounted at boot:

	shmfs       /dev/shm     shm    defaults        0       0
    

      (Note: you may have to make the /dev/shm directory)

<unsnip>

Is this the actual use of /dev/shm or can it serve dual purpose and be 
also set up as tmpfs for fifo's?


Or...

<snip>

|# mkdir /mnt/ramfs|

[edit /etc/fstab and add the following line]

|none /mnt/ramfs tmpfs defaults 0 0|

Then use --with-default-tmpdir=/mnt/ramfs to the JACK configure line 
when you build it. No clients need to be recompiled.

<unsnip>

Is this the better or just alternative option?

Thanks
R~







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