Tutorial: Realtime (RT) Audio on Linux: The Basics (for Laymen)

[belevtsoff]

I'm afraid all it does is just allows a non-root user to renice processes. In order to get hard real-time perfomance one needs to run patched kernel. I tried doing things adviced in this video but got no perfomance increase (comared to same thing ran with root). After patching a kernel I can run JACK with under 1ms latency with no Xrun's. Cheers

[wtilkin]

This video is a nice tutorial to optimize the standard linux for realtime audio, but it's still using soft real-time kernel, which has nothing to do with hard real time does it?

[Komputerism]

I can run my nord rack2 with hydrogen drum machine cortoled by seq24 now. thank you.

[Wintershade3001]

@1:48 Finally! Somebody making a sane statement about linux-rt kernel. Thank you, friend.

[Don70rEnZ0]

Great way of explaining and teaching us, thank you for your kind work,

[jaaxxone]

Not sure about setting your limits at the user level. Would be better to use the @audio group so only those processes get the increased privs. Otherwise, any old user process (gnome panel, notifications, browsers, etc) can steal resources during the middle of your recording sessions!

[jkymarsh]

@jaaxxone This is untrue. First off, placing users within in Audio group doesn't have anything to do with determining what programs use RT priorities; it's simply a naming system used to keep things straight if a lot of users use your system. Programs don't know (or care) what user group you're a member of. Secondly, programs don't inherently use unbounded amounts of system resources; they have to specifically be configured to do so.

[icemanguitar]

tahnk you thank you =) =)

[aynrandy1]

I'm in MEPIS, so I had to log into the actual root login to make these changes.

I couldn't save the changes from my user account with root privileges.

But it worked fine after changing it in the actual root account of MEPIS.

[Ejacka]

Changed file permissions:

sudo chmod limits.conf -rwxrwxrwx

but got this message:

"Could not save the file /etc/security/limits.conf.

You are trying to save the file on a read-only disk. Please check that you typed the location correctly and try again."

[jkymarsh]

@Ejacka Try actually logging in as root rather than using sudo. If that doesn't work, you may want to alter your chmod tactic... Using chmod ugo=rwx (or some variation thereof) has always been more reliable and straightforward for me. (Also, doesn't a hyphen before the permissions arguments remove from a file/directory?)

[bbglas007]

Legend! Thanks for this!

[cothedo]

Thanks for posting this tutorial, it really helped!

[fatsterfatster]

INteresting, but one thing I don't understand is what's the difference between soft and hard limits and the "-" ?

[jkymarsh]

@fatsterfatster A soft limit is a default value when a user logs in, and this value can be increased using the terminal "ulimit" command. However, we're not interested in either a soft limit or a hard maximum limit, nor using "ulimit" to manually change anything, so we don't have to bother with hard or soft at all.

[JD4x4]

Wish you had been here 3 years ago when I first started the move from XP to Ubuntu!

Thank you, Thank you! This is REALLY helpful to those of us trying to understand the 'inside' of linux/Ubuntu. Your step-by-step explanations did the job for me. I sense that this may well be the start of finally removing my dual-boot & XP!

[jkymarsh]

@JD4x4 Thanks for the kind words! Glad it helped! If there's anything else you'd like a tutorial for, let me know.

[pooh1234567890]

Ah i see thanks for that

[pooh1234567890]

Hi, I still don't understand real time audio, wouldn't changing this config file make every program use maximum system resources, how does it only let audio programs use it?

[jkymarsh]

@pooh1234567890 Programs that can make use of realtime priority must have a software switch specifically stating to use RT. For example, JACK has an option stating "Realtime priority." Most programs do not contain this option.