Dev1 Galaxy Forum / Devuan running very slow on Raspberry PI 3 b+

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (spinlock) — Thu, 31 Jan 2019 15:45:23 +0000

spartrekus wrote:

1) KERNEL
uname -a
Linux devuan 4.16.14-v8+ #1 SMP PREEMPT Tue Jun 5 18:50:10 CEST 2018 aarch64 GNU/Linux
uname -a #1159 SMP Sun Nov 4 17:50:20 GMT 2018 armv7l GNU/Linux
Linux raspberrypi 4.14.79-v7+ #1159 SMP Sun Nov 4 17:50:20 GMT 2018 armv7l GNU/Linux
ls /lib/modules/
4.14.79+ 4.14.79-v7+

Unless one needs native aarch64 for a particular task, there seem to be few advantages to running a 64-bit kernel on a Raspberry Pi, especially given the limited RAM.

Performance of the 32-bit rpi2 devuan build is generally better, though it is not very easy to install on the rpi3 (any version). The 06-Jun-2018 dated images hosted on devuan.org do not work on rpi3 or the BCM2837 based rpi2+ (the documentation on devuan.org is incorrect). One has to rebuild the image using the arm-sdk:

https://git.devuan.org/sdk/arm-sdk

This is somewhat tedious, but results in a bootable image.

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (spartrekus) — Fri, 18 Jan 2019 16:41:06 +0000

After many tries, and tries, I come to conclusion that it comes from the operating system, likely kernel of devuan.

Raspbian is much faster than devuan,
FreeBSD is much faster than Raspbian for non X-heavy application, but chrome/chromium is the fastest on the raspbian.

Comparison with blackbox and icewm, and minimal installation.

It depends mostly from the given OS kernel I believe.

Tested with (10) scandisk 16mb, good one actually.

1) KERNEL
uname -a
Linux devuan 4.16.14-v8+ #1 SMP PREEMPT Tue Jun 5 18:50:10 CEST 2018 aarch64 GNU/Linux

uname -a #1159 SMP Sun Nov 4 17:50:20 GMT 2018 armv7l GNU/Linux
Linux raspberrypi 4.14.79-v7+ #1159 SMP Sun Nov 4 17:50:20 GMT 2018 armv7l GNU/Linux
ls /lib/modules/
4.14.79+ 4.14.79-v7+

2) CHROMIUM
How to make chromium runs faster.
Devuan will give slow reaction of chromium, i.e. visible on youtube.com. Slow videos, for instance.

Raspbian runs faster for chromium-browser .
Fastest way to get chromium-browser raspbian fast:
get lite zip raspbian and bring it up.

apt-get update ; apt-get install -y --no-install-recommends chromium-browser xinit xterm icewm

enjoy

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (kuleszdl) — Sun, 30 Dec 2018 15:17:39 +0000

The UHS specification is not very relevant and also the capacity matters. Here are some 4K random read/write values I measured:

- Sandisk Ultra A1 200 GB: 8.54 MB/s read, 5.13 MB/s write
- Sandisk Extreme A2 64 GB: 4.97 MB/s read, 3.05 MB/s write
- Sandisk Ultra A1 64 GB: 7.67 MB/s read, 2.84 MB/s write
- Sandisk Ultra C10 64GB: 5.26 MB/s read, 0.94 MB/s write
- Toshiba Exceria UHS-3 64GB: 3.82 MB/s read, 0.09 MB/s write

In this sample you can see with the Exceria UHS-3 card that there are extreme cases of cards that have good linear read/write performance with large block sizes of roundabout 100 MB/s but they suck extremely when it comes to 4K random read/write. But this is what actually matters for a system drive.

I had a more comprehensive list of measures on my blog that is currently offline. But you can find another comparison and a link to a recent 2018 update in Jeff Garling's blog over here (unlike me, he measured directly on the RPi's internal card reader):

https://www.jeffgeerling.com/blogs/jeff … crosd-card

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (freenet_bro) — Sun, 30 Dec 2018 06:47:06 +0000

I never ever tried Raspbian, because Systemd. But I can say, that my raspberry pi with Devuan feels pretty snappy. I use SanDisk Ultra microSDXC UHS-I Card. It has 100MB/s read speed and a decent write speed.

Devuan for life. <3

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (Lomax) — Sat, 29 Dec 2018 22:44:47 +0000

This might be relevant:

guidol wrote:

I installed the RPi1 version of devuan on the ZeroW, but did wonder why it seems to be slower than on raspbian lite.
After searching I did found that devuan uses the CPU governor "powersave" while raspbian uses "ondemand"
So after give the command
echo 'ondemand' > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
devuan should work fast as raspbian on a Raspberry Pi Zero W

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (spartrekus) — Sat, 22 Dec 2018 19:16:39 +0000

Thank you for your message.

I am glad to read that it could be less so slow. hopefully.

On the same SD card, I installed FreeBSD and it runs faster. With icewm it takes about 20 mb.

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (kuleszdl) — Thu, 20 Dec 2018 11:44:40 +0000

Regarding the SD Cards: What really matters here is the performance with 4K random read/write, and many U3 cards do not perform here well, either. I recommend cards with the A1 standard - Sandisk is a good choice, also the Samsung Evo+ series is a good pick.

If you want to compare yourself, use iozone (open source but non-free) to do the benchmarks yourself.

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (basati) — Tue, 18 Dec 2018 21:20:32 +0000

That scandisk card is not the most appropriate to opt for performance

The best option is a SDXC I protocol U3 card with 100mb/s read and 90mb/s read.

Luckily they've come down a lot in price. A samnsung evo 64gb is a good choice and I think they are at about 18€.

The ones from amazon sell it here:

https://www.amazon.es/gp/product/B06XFW … UTF8&psc=1

Note that the 32gb is NOT U3 protocol.

I'm working on a version of the raspi3 image we have because it's in balls. A normal user can't do anything with it.

With a desktop XFCE, libreoffice, etc. etc. goes very loose. Watch out, you have to keep in mind what a raspberry is and the very big limitations that tiesne. You need to be patient and wait for the programs to open. If in firefox you open a lot of eyelashes is piled up and hung.

I use several cards, instable, testing and stable. as in devuan.

I'm going step by step. but you have to do everything by hand. I'm writing a HowTo at the same time to make the image we have usable.

I have tried an application of raspian raspi-config does not work at all for us, but THAT is something we NEED. I couldn't find the package in raspian's poll. So I made an image of raspian uninstall the application and reinstall it. And obviously the package was in /var/cache/apt

8=þ

To try this not bad. You realize a GIANT lack that we have. So to speak somehow with "four clicks" you have configured the raspberry. I have used it in console and graphical environment.

What that application does to me, costs me a lot more than an hour.

When the HowTo is ready then the thing will be simpler but at hand.

Greetings

basati

Re: Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (rmrichesjr) — Tue, 18 Dec 2018 19:35:28 +0000

A couple of suggestions until somebody who really knows what they're talking about shows up:

1) Use "top" to see whether something is hogging the CPUs.

2) Use "vmstat 3" to see whether something is hogging disk bandwidth and to see what disk bandwidth you are getting.

Devuan running very slow on Raspberry PI 3 b+

dummy@example.com (spartrekus) — Tue, 18 Dec 2018 07:48:29 +0000

Hello,

I have installed Devuan on SDcard, and it runs quite slow actually.
employed file: -> devuan_ascii_2.0.0_arm64_raspi3.img.xz 06-Jun-2018 11:28 153M

I installed only blackbox, xpaint, scribus, links, dillo, git and subversion.

The SD card is scandisk model 10, pretty good actually. However, performances could be better.

Which improvements would be possible to get Linux faster?