[Jack-Devel] advice on xruns

[Ralf Mardorf]

On Sun, 2019-07-28 at 11:19 +0200, Holger Marzen wrote:
> With audit=0 I can use a buffer size of 12 at 48000 Hz and 2 buffers to
> Play a mixcloud song with Firefox -> Pulseaudio -> jackd and get no
> xruns.

So in the meantime you already found the kernel-parameter and the
detailed information by the kernel docs, that I didn't know :).

You could use ½ of the frames, 12 instead of 24, just by disabling
audit, too?

What kernel are you using?

I should consider to test disabling spectre mitigations and audit by
kernel parameters, too.

Until now I didn't make much tests, for example just:

[rocketmouse at archlinux ~]$ uname -rm
4.19.59-rt24-0-securityink x86_64
[rocketmouse at archlinux ~]$ grep CONFIG_AUDIT= /usr/lib/modules/$(uname -r)/build/.config 
CONFIG_AUDIT=y
[rocketmouse at archlinux ~]$ cat /sys/devices/system/cpu/vulnerabilities/*
Mitigation: PTE Inversion; VMX: conditional cache flushes, SMT disabled
Mitigation: Clear CPU buffers; SMT disabled
Mitigation: PTI
Mitigation: Speculative Store Bypass disabled via prctl and seccomp
Mitigation: __user pointer sanitization
Mitigation: Full generic retpoline, IBPB: conditional, IBRS_FW, STIBP: disabled, RSB filling
[rocketmouse at archlinux ~]$ grep LABEL\ Securityink /boot/syslinux/syslinux.cfg -A4
LABEL Securityink
    MENU LABEL Arch Linux Rt ^Securityink
    LINUX ../vmlinuz-linux-rt-securityink
    APPEND root=LABEL=s3.archlinux ro
    INITRD ../intel-ucode.img,../initramfs-linux-rt-securityink.img
--
LABEL Securityink_no_micro
    MENU LABEL Arch Linux Rt Securityink no micro
    LINUX ../vmlinuz-linux-rt-securityink
    APPEND root=LABEL=s3.archlinux ro
    INITRD ../initramfs-linux-rt-securityink.img
--
LABEL Securityink_nopti
    MENU LABEL Arch Linux Rt Securityink nopt^i
    LINUX ../vmlinuz-linux-rt-securityink
    APPEND root=LABEL=s3.archlinux ro nopti
    INITRD ../intel-ucode.img,../initramfs-linux-rt-securityink.img
[rocketmouse at archlinux ~]$ hwinfo --cpu | grep Model | sort -u
  Model: 6.60.3 "Intel(R) Celeron(R) CPU G1840 @ 2.80GHz"

-- 
pacman -Q linux{,-rt{-cornflower,-pussytoes,,-securityink}}|cut -d\  -f2
5.2.3.arch1-1
5.2_rt1-0
5.0.21_rt16-1
5.0.19_rt11-1
4.19.59_rt24-0