System optimizations?

[hifix]

The only tweaks I have applied are the following:

- added in /boot/cmdline.txt: isolcpus=2,3
- changed options in /lib/systemd/system/mpd.service
    CPUSchedulingPolicy=fifo
    CPUSchedulingPriority=70
    Nice=-15
    ExecStart=/usr/bin/taskset -c 2,3 /usr/local/bin/mpd --no-daemon $MPDCONF

I did not change anything else. This made some difference!  In fact, because of the fact that mpd and its subprocesses run on two reserved cores, and nothing else runs on those cores, you should get all the advantages of LL and RT kernels.

  Roberto

Its all sounding very nice now

Has anyone been game to try the whole list of tweaks from the DIY forum as swizzle has pointed out ?
http://www.diyaudio.com/forums/pc-based/...ost5398891

Also tried this tweak (3.8.4), it worked (it sounded more open) but I couldn't reboot / shutdown the RPI/Moode anymore using the menu functionality from the GUI...

Sorry to hear about the reboot issue.
I have been playing around with some of the parameters and i've not experienced a loss of functionality (i'm running an audiophonics power management script which is needed for my setup - but i dont think this changes anything).

Have you made any other changes ?

[mactolinux]

I did optimisations as described (core isolation, lower frequencies and power etc). I used Rune settings, meaning reducing power for SDRAM (not increasing).

Just to confirm what I heard yesterday and read here now:

1. Yes, there's definite improvement in imaging: stage became very clear, focused and stable now, that's amazing.

2. Yes, harsh on high frequencies reduced. It is almost good! This harsh was the most annoying with MPD.


With the struggle between MOC Player, MacOS (Audirvana) and MoOde (MPD) I rather choose last one now. MOC has blurred stage and smooth frequencies at highs, it is sonically attractive... but I can live with MPD. Audirvana now is in the middle between two.

P.S.
I have an external USB-Dac (Amanero USB module on its own separate power + PCM58 multibit, non-oversampling mode). Followed by 2A3-amp and open baffles (3 ways speaker system).

[rikardo1979]

Just testing these tweaks on latest 4.3 and I can say that I hear a real sonic improvement on my system including RaspDAC I-Sabre V3 ES9023 TXCO 

Now I just need more time to listen to the system.

One thing I found annoying so far, the system is a bit slower when loading track. Looks its need a more time to buffer.

Will report back with more info after some time

[jonners]

I'm getting a bit confused as to the exact tweaks that are being used here now. Is it as moodenigo posted above?

[rikardo1979]

I'm getting a bit confused as to the exact tweaks that are being used here now. Is it as moodenigo posted above?

I testing the whole lot, that includes those settings in /boot/config.txt

[mactolinux]

Mine, as a combination from different sources. Please note, I isolated one core for MPD, but didn't try more.
I would say now the power quality is more important.

1.
sudo nano /boot/cmdline.txt

net.ifnames=0 console=serial0,115200 console=tty1 root=PARTUUID=4d3ee428-02 rootfstype=ext4 fsck.repair=yes rootwait dwc_otg.microframe_schedule=0 dwc_otg.nak_holdoff_enable=1 dwc_otg.fiq_fix_enable=0 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 elevator=noop isolcpus=3

2.
sudo nano /boot/config.txt

disable_splash=1
hdmi_drive=2
dtparam=i2c_arm=off
dtparam=i2s=off
dtparam=audio=on
#dtoverlay=pi3-disable-wifi
dtoverlay=pi3-disable-bt
start_x=0

max_usb_current=1

# memory options
gpu_mem=16

# Overclocking options
force_turbo=1
initial_turbo=60

avoid_pwm_pll=1
arm_freq=666
over_voltage=-6
gpu_freq=333

# sdram overclock
sdram_freq=333

sdram_schmoo=0x02000020
over_voltage_sdram_p=-5
over_voltage_sdram_i=-14
over_voltage_sdram_c=-6

disable_pvt=1

# HDMI disable
hdmi_blanking=2

3.
sudo nano /lib/systemd/system/mpd.service

[Service]
# Real-time / Low latency params
# ps -e -o class,rtprio,pri,nice,cmd
# for real-time scheduling policies the "nice" param is ignored and the pri column is not relevant
ExecStart=/usr/bin/taskset -c 3 /usr/local/bin/mpd --no-daemon $MPDCONF
Restart=always


-------------- (note) At the very end of original script add # once at ExecStart:
# Launch params
EnvironmentFile=/etc/default/mpd
#ExecStart=/usr/local/bin/mpd --no-daemon $MPDCONF

#CPUSchedulingPolicy=other
CPUSchedulingPolicy=fifo
#CPUSchedulingPriority=43
CPUSchedulingPriority=70
Nice=-18


Updated: forgot core isolation line here, just added. Sorry.

[jonners]

@rikardo1979 and @mactolinux
Thanks for clarifying.

[mactolinux]

One more addition. mpd.service, CPUSchedulingPolicy=fifo cause to stops for high resolution files in FLAC/ALAC. Whatever other settings you set. Therefore, if you do have some, leave it as CPUSchedulingPolicy=other

[rikardo1979]

@mactolinux are you sure about that statement? I think you are not right here as I use CPUSchedulingPolicy=fifo

I have no problem with playback of hires FLACs or even DSD files

[mactolinux]

Okay... Maybe that caused by USB DAC in my case, not internal i2s.

I’ve tried many times, for me it is only “other” setting.

Whatever source I use for the files, fast SD-card or HDD.