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swap-fle on arm64, need to disable, how?

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  swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-09-29 21:20 +0200
    Re: swap-fle on arm64, need to disable, how? Andy Smith <andy@strugglers.net> - 2023-09-29 21:30 +0200
      Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-09-29 22:40 +0200
        Re: swap-fle on arm64, need to disable, how? Andy Smith <andy@strugglers.net> - 2023-09-29 23:40 +0200
          Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-09-30 09:30 +0200
            Re: swap-fle on arm64, need to disable, how? Andy Smith <andy@strugglers.net> - 2023-09-30 13:50 +0200
              Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-09-30 17:20 +0200
                Re: swap-fle on arm64, need to disable, how? Andy Smith <andy@strugglers.net> - 2023-09-30 22:20 +0200
                  Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 02:30 +0200
                    Re: swap-fle on arm64, need to disable, how? Curt <curty@free.fr> - 2023-10-01 17:10 +0200
                      Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 19:00 +0200
            Re: swap-fle on arm64, need to disable, how? David Wright <deblis@lionunicorn.co.uk> - 2023-09-30 20:20 +0200
        Re: swap-fle on arm64, need to disable, how? Max Nikulin <manikulin@gmail.com> - 2023-09-30 03:30 +0200
    Re: swap-fle on arm64, need to disable, how? Matthias Böttcher <matthias.boettcher@gmail.com> - 2023-09-30 19:30 +0200
      Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-09-30 20:00 +0200
        Re: swap-fle on arm64, need to disable, how? Greg Wooledge <greg@wooledge.org> - 2023-09-30 20:20 +0200
          Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 01:50 +0200
          Re: swap-fle on arm64, need to disable, how? Max Nikulin <manikulin@gmail.com> - 2023-10-01 10:20 +0200
        Re: swap-fle on arm64, need to disable, how? Matthias Böttcher <matthias.boettcher@gmail.com> - 2023-09-30 21:30 +0200
      Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 00:40 +0200
        Re: swap-fle on arm64, need to disable, how? Stefan Monnier <monnier@iro.umontreal.ca> - 2023-10-01 04:30 +0200
        Re: swap-fle on arm64, need to disable, how? hw <hw@adminart.net> - 2023-10-01 05:30 +0200
          Re: swap-fle on arm64, need to disable, how? Max Nikulin <manikulin@gmail.com> - 2023-10-01 10:10 +0200
            Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 11:10 +0200
              Re: swap-fle on arm64, need to disable, how? Greg Wooledge <greg@wooledge.org> - 2023-10-01 15:00 +0200
                Re: swap-fle on arm64, need to disable, how? "Andrew M.A. Cater" <amacater@einval.com> - 2023-10-01 15:40 +0200
                  Re: swap-fle on arm64, need to disable, how? David Wright <deblis@lionunicorn.co.uk> - 2023-10-01 17:40 +0200
                  Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 19:00 +0200
                Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 18:50 +0200
                  Re: swap-fle on arm64, need to disable, how? Stefan Monnier <monnier@iro.umontreal.ca> - 2023-10-01 20:10 +0200
                    Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 21:20 +0200
                      Re: swap-fle on arm64, need to disable, how? Stefan Monnier <monnier@iro.umontreal.ca> - 2023-10-02 00:50 +0200
                        Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-04 10:10 +0200
          Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-01 10:40 +0200
            Re: swap-fle on arm64, need to disable, how? David Wright <deblis@lionunicorn.co.uk> - 2023-10-01 17:40 +0200
            Re: swap-fle on arm64, need to disable, how? hw <hw@adminart.net> - 2023-10-01 22:10 +0200
              Re: swap-fle on arm64, need to disable, how? gene heskett <gheskett@shentel.net> - 2023-10-02 02:00 +0200
              Re: swap-fle on arm64, need to disable, how? Max Nikulin <manikulin@gmail.com> - 2023-10-03 04:40 +0200

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#262028

> But I cannot label the partition.  At least not with gparted.  I did
> generate a new blkid then put the partuuid in fstab, rebooted it and
> that worked.

This sounds to me like a subliminal message telling me "see all the pain
you avoided by using LVM instead".


        Stefan

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#262030

On Sat, 2023-09-30 at 18:29 -0400, gene heskett wrote:
> On 9/30/23 13:28, Matthias Böttcher wrote:
> > sudo dphys-swapfile swapoff
> > sudo systemctl stop dphys-swapfile.service
> > sudo systemctl disable dphys-swapfile.service
> > 
> > .
> However that did give me a clue about getting rid of zram0, which has 
> been done now, thank you. Now I hope to uncomment the SSD line in fstab.

Well, zram is the way to go; why would you still use swap partitions
or swap files instead?  Are you deliberately trying to wear out your
SSDs or to slow down your computer?

Fedora has it by default since a while, and at first I thought it's a
very stupid idea.  In practise, I can't be bothered anymore to create
these annoying swap partitions.  They're only a waste of disc space.
There haven't been any issues with it, and when the machine runs out
of memory, using swap partitions or swap files isn't going to fix
that.

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#262033

On 01/10/2023 10:21, hw wrote:
> Well, zram is the way to go; why would you still use swap partitions
> or swap files instead?

The topic of this thread is a *Pi board. It does not have as much RAM as 
significant part of x86_64 laptops and desktops with installed Fedora.

It seems, Gene it trying to run some CNC software and Firefox to control 
it, perhaps some CAD. I suspect that some of mysterious issues are 
caused by not enough RAM. Adding swap on a hard drive instead of ZRAM 
may relief some issues.

However I would consider moving most of application to another machines. 
My suggestion is to monitor RAM usage and to avoid overloading of *Pi 
boards. Perhaps swap may be still necessary for complicated CNC tasks.

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#262036

On 10/1/23 04:05, Max Nikulin wrote:
> On 01/10/2023 10:21, hw wrote:
>> Well, zram is the way to go; why would you still use swap partitions
>> or swap files instead?
> 
> The topic of this thread is a *Pi board. It does not have as much RAM as 
> significant part of x86_64 laptops and desktops with installed Fedora.
> 
> It seems, Gene it trying to run some CNC software and Firefox to control 
> it, perhaps some CAD. I suspect that some of mysterious issues are 
> caused by not enough RAM. Adding swap on a hard drive instead of ZRAM 
> may relief some issues.
> 
> However I would consider moving most of application to another machines. 
> My suggestion is to monitor RAM usage and to avoid overloading of *Pi 
> boards. Perhaps swap may be still necessary for complicated CNC tasks.
> 
> .
You've a good view of this hw. However swap is not important to run 
linuxcnc, in fact its to be avoided because it messes with realtime 
response. Linuxcnc needs, even with much of the control offloaded to 
mesa and similar smart cards, it still needs to check what the machine 
is doing 1000 times a second. The way I'm doing it, the wobble in this 
timing as 50 to 80 microseconds, which doesn't bother the machine all 
that much, the real time killer is firing up firefox which can lock out 
the irq response for hundreds of milliseconds.  So I don't carve metal 
and browse the web at the same time.  I added some dials and decoders so 
I can run this lathe, which only has 3 motors, and no compound at all, 
by hand using the dials as hand cranks. Originally doing this on an 
rpi3b when it was new in the 2017-2018 timeframe, I put all the hand 
control stuff in a slower 200 hz thread since I can't turn the dials any 
faster by hand anyway. Its still there. Linuxcnc, driving the two 
motors, is a far more accurate compound than the broken compound I've 
removed ever was.  The third motor is driving the spindle at 
continuously variable speeds with an encoder telling linuxcnc where the 
spindle is 240 times a revolution.  There are no change gears, yet it 
can cut any thread, inch or metric including some I've dreamed up. 
Sub-micron accurate at any angle.  Whats not to like?

Take care & stay well.

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>

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#262040

On Sun, Oct 01, 2023 at 05:07:48AM -0400, gene heskett wrote:
> You've a good view of this hw. However swap is not important to run
> linuxcnc, in fact its to be avoided because it messes with realtime
> response. Linuxcnc needs, even with much of the control offloaded to mesa
> and similar smart cards, it still needs to check what the machine is doing
> 1000 times a second. The way I'm doing it, the wobble in this timing as 50
> to 80 microseconds, which doesn't bother the machine all that much, the real
> time killer is firing up firefox which can lock out the irq response for
> hundreds of milliseconds.  So I don't carve metal and browse the web at the
> same time.

If Firefox is really just for "browsing the web", and is not part of
the user interface for the CNC pieces, I don't understand why you run
Firefox on this machine at all.  I would run the browser on a separate
computer, one which isn't so critical to your operation.

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#262041

On Sun, Oct 01, 2023 at 08:58:36AM -0400, Greg Wooledge wrote:
> On Sun, Oct 01, 2023 at 05:07:48AM -0400, gene heskett wrote:
> > You've a good view of this hw. However swap is not important to run
> > linuxcnc, in fact its to be avoided because it messes with realtime
> > response. Linuxcnc needs, even with much of the control offloaded to mesa
> > and similar smart cards, it still needs to check what the machine is doing
> > 1000 times a second. The way I'm doing it, the wobble in this timing as 50
> > to 80 microseconds, which doesn't bother the machine all that much, the real
> > time killer is firing up firefox which can lock out the irq response for
> > hundreds of milliseconds.  So I don't carve metal and browse the web at the
> > same time.
> 
> If Firefox is really just for "browsing the web", and is not part of
> the user interface for the CNC pieces, I don't understand why you run
> Firefox on this machine at all.  I would run the browser on a separate
> computer, one which isn't so critical to your operation.
>

Echoing Greg:

2G is a fairly small amount of memory - by default the *Debian* install
for RPi 4 now gives you 1G of swap on whatever medium - which you should
never need to use.

It would make sense for something real time critical to be on a 2GB or 4GB RPi
on it's own - if you're running modellers or whatever for 3D printing, that
might be different but a command line or simplest web interface might be
best. You REALLY don't want anything extraneous.

Pi 4GB or 8GB are now available more or less: your BananaPi - you are *very*
much on your own.

All best, sa ever,

Andy
[amacater@debian.org] 

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#262048

On Sun 01 Oct 2023 at 13:39:17 (+0000), Andrew M.A. Cater wrote:
> On Sun, Oct 01, 2023 at 08:58:36AM -0400, Greg Wooledge wrote:
> > On Sun, Oct 01, 2023 at 05:07:48AM -0400, gene heskett wrote:
> > > You've a good view of this hw. However swap is not important to run
> > > linuxcnc, in fact its to be avoided because it messes with realtime
> > > response. Linuxcnc needs, even with much of the control offloaded to mesa
> > > and similar smart cards, it still needs to check what the machine is doing
> > > 1000 times a second. The way I'm doing it, the wobble in this timing as 50
> > > to 80 microseconds, which doesn't bother the machine all that much, the real
> > > time killer is firing up firefox which can lock out the irq response for
> > > hundreds of milliseconds.  So I don't carve metal and browse the web at the
> > > same time.
> > 
> > If Firefox is really just for "browsing the web", and is not part of
> > the user interface for the CNC pieces, I don't understand why you run
> > Firefox on this machine at all.  I would run the browser on a separate
> > computer, one which isn't so critical to your operation.
> >
> Echoing Greg:
> 
> 2G is a fairly small amount of memory - by default the *Debian* install
> for RPi 4 now gives you 1G of swap on whatever medium - which you should
> never need to use.
> 
> It would make sense for something real time critical to be on a 2GB or 4GB RPi
> on it's own - if you're running modellers or whatever for 3D printing, that
> might be different but a command line or simplest web interface might be
> best. You REALLY don't want anything extraneous.
> 
> Pi 4GB or 8GB are now available more or less: your BananaPi - you are *very*
> much on your own.

Back in 2018, Gene's explanation was:

  https://lists.debian.org/debian-user/2018/11/msg00049.html

Cheers,
David.

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#262052

On 10/1/23 09:39, Andrew M.A. Cater wrote:
> On Sun, Oct 01, 2023 at 08:58:36AM -0400, Greg Wooledge wrote:
>> On Sun, Oct 01, 2023 at 05:07:48AM -0400, gene heskett wrote:
>>> You've a good view of this hw. However swap is not important to run
>>> linuxcnc, in fact its to be avoided because it messes with realtime
>>> response. Linuxcnc needs, even with much of the control offloaded to mesa
>>> and similar smart cards, it still needs to check what the machine is doing
>>> 1000 times a second. The way I'm doing it, the wobble in this timing as 50
>>> to 80 microseconds, which doesn't bother the machine all that much, the real
>>> time killer is firing up firefox which can lock out the irq response for
>>> hundreds of milliseconds.  So I don't carve metal and browse the web at the
>>> same time.
>>
>> If Firefox is really just for "browsing the web", and is not part of
>> the user interface for the CNC pieces, I don't understand why you run
>> Firefox on this machine at all.  I would run the browser on a separate
>> computer, one which isn't so critical to your operation.
>>
> 
> Echoing Greg:
> 
> 2G is a fairly small amount of memory - by default the *Debian* install
> for RPi 4 now gives you 1G of swap on whatever medium - which you should
> never need to use.
> 
> It would make sense for something real time critical to be on a 2GB or 4GB RPi
> on it's own - if you're running modellers or whatever for 3D printing, that
> might be different but a command line or simplest web interface might be
> best. You REALLY don't want anything extraneous.
> 
> Pi 4GB or 8GB are now available more or less: your BananaPi - you are *very*
> much on your own.
> 
> All best, sa ever,
> 
> Andy
> [amacater@debian.org]
> 
> .
The bananapi-m5 at $80 USD is very much the superior pi except for no 
radio, 4 core cpu at 2 GHz, w/o a fan, 4G of dram, 16G of m2 disk 
onboard, and all 4 usb ports are usb3 speed. The armbian install runs on 
ubuntu jammy repos. Got a pile of them here.

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>

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#262050

On 10/1/23 08:59, Greg Wooledge wrote:
> On Sun, Oct 01, 2023 at 05:07:48AM -0400, gene heskett wrote:
>> You've a good view of this hw. However swap is not important to run
>> linuxcnc, in fact its to be avoided because it messes with realtime
>> response. Linuxcnc needs, even with much of the control offloaded to mesa
>> and similar smart cards, it still needs to check what the machine is doing
>> 1000 times a second. The way I'm doing it, the wobble in this timing as 50
>> to 80 microseconds, which doesn't bother the machine all that much, the real
>> time killer is firing up firefox which can lock out the irq response for
>> hundreds of milliseconds.  So I don't carve metal and browse the web at the
>> same time.
> 
> If Firefox is really just for "browsing the web", and is not part of
> the user interface for the CNC pieces, I don't understand why you run
> Firefox on this machine at all.  I would run the browser on a separate
> computer, one which isn't so critical to your operation.
> 
There I disagree, Greg, it makes a handy download tool, directly from 
wherever, directly to the machine that needs it.  That, apt/synaptic and 
git are the major net tools I use.  Obviously I'm not trying to run them 
simultaneously. Every machine here 7 ATM, can browse the net, making it 
very easy to keep them up to date.
> .

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>

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#262058

> There I disagree, Greg, it makes a handy download tool, directly from
> wherever, directly to the machine that needs it.  That, apt/synaptic and git
> are the major net tools I use.  Obviously I'm not trying to run them
> simultaneously. Every machine here 7 ATM, can browse the net, making it very
> easy to keep them up to date.

Do you have some big honking KVM to multiplex all those machines
onto your screen and keyboard, or do you actually have 7 screens and
7 keyboards and you need to walk over from one to the other?

Personally, I think I'd do neither: I'd have all those little buggers
headless and control them exclusively remotely via SSH (there could be
some alternatives like remote desktop or web-server UIs, but I find the
command line just a lot more convenient).
[ That's what I do with my BananaPi and my Odroid servers.  ]


        Stefan

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#262065

On 10/1/23 14:06, Stefan Monnier wrote:
>> There I disagree, Greg, it makes a handy download tool, directly from
>> wherever, directly to the machine that needs it.  That, apt/synaptic and git
>> are the major net tools I use.  Obviously I'm not trying to run them
>> simultaneously. Every machine here 7 ATM, can browse the net, making it very
>> easy to keep them up to date.
> 
> Do you have some big honking KVM to multiplex all those machines
> onto your screen and keyboard, or do you actually have 7 screens and
> 7 keyboards and you need to walk over from one to the other?
> 
Here I was going to ask if you'd ever hear of ssh and sshfs. but thn I 
read the next paragraph.

> Personally, I think I'd do neither: I'd have all those little buggers
> headless and control them exclusively remotely via SSH (there could be
> some alternatives like remote desktop or web-server UIs, but I find the
> command line just a lot more convenient).
> [ That's what I do with my BananaPi and my Odroid servers.  ]

And Odroid?  Where do I send condolence flowers? I spent several days 
trying to install a linux on it. Wound up bricking it. That outfit is 
married to uefi and our socalled shim was nowhere near ready for prime 
time. They said I'd need to get about $275 in jtag tools to unbrick it. 
When I took my problem with that back I was told our way or or the 
hiway. So I ordered a rpi3b and did the job with it.  They will never 
see another penny from me. That is their problem, I use what works, and 
theirs didn't.

> 
>          Stefan
> 
> .

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>

[toc] | [prev] | [next] | [standalone]

#262079

>>> There I disagree, Greg, it makes a handy download tool, directly
>>> from wherever, directly to the machine that needs it.  That,
>>> apt/synaptic and git are the major net tools I use.  Obviously I'm
>>> not trying to run them simultaneously. Every machine here 7 ATM, can
>>> browse the net, making it very easy to keep them up to date.
>> Do you have some big honking KVM to multiplex all those machines
>> onto your screen and keyboard, or do you actually have 7 screens and
>> 7 keyboards and you need to walk over from one to the other?
> Here I was going to ask if you'd ever hear of ssh and sshfs. but thn I read
> the next paragraph.

Then why do you need to run firefox on the rpi's?  I'd use Firefox on my
desktop and if I need to download files to one of the other machines,
I'd copy those files via `scp` or `sshfs` or even NFS (NFS
authentication is a PITA in my experience, but if you can use
a dedicated local network where you all machines can somewhat trust
each other, NFS can be a good option).

> And Odroid?  Where do I send condolence flowers?

I was not super happy with some aspects (e.g. the fact that I can't get
the source code for some of the firmware, including the Petitboot that's
included, nor is there any way to change that firmware's config (e.g. to
make Petitboot use the serial console rather than the HDMI output)), but
in practice it works well and the hardware is fully supported by the
vanilla Linux kernel.


        Stefan

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#262154

On 10/1/23 18:46, Stefan Monnier wrote:
>>>> There I disagree, Greg, it makes a handy download tool, directly
>>>> from wherever, directly to the machine that needs it.  That,
>>>> apt/synaptic and git are the major net tools I use.  Obviously I'm
>>>> not trying to run them simultaneously. Every machine here 7 ATM, can
>>>> browse the net, making it very easy to keep them up to date.
>>> Do you have some big honking KVM to multiplex all those machines
>>> onto your screen and keyboard, or do you actually have 7 screens and
>>> 7 keyboards and you need to walk over from one to the other?
>> Here I was going to ask if you'd ever hear of ssh and sshfs. but thn I read
>> the next paragraph.
> 
> Then why do you need to run firefox on the rpi's?  I'd use Firefox on my
> desktop and if I need to download files to one of the other machines,
> I'd copy those files via `scp` or `sshfs` or even NFS (NFS
> authentication is a PITA in my experience, but if you can use
> a dedicated local network where you all machines can somewhat trust
> each other, NFS can be a good option).

NFS is a pita.
sshfs just works for file movement. ssh -X for login stuff. It helps of 
course that I am the only "live user"

>> And Odroid?  Where do I send condolence flowers?
> 
> I was not super happy with some aspects (e.g. the fact that I can't get
> the source code for some of the firmware, including the Petitboot that's
> included, nor is there any way to change that firmware's config (e.g. to
> make Petitboot use the serial console rather than the HDMI output)), but
> in practice it works well and the hardware is fully supported by the
> vanilla Linux kernel.
> 
It wasn't anywhere near primetime ready when I bought on 7 or 8 years 
ago. Actually supporting linux was not then a prioirty. I use winderz 
stuff for target practice here.
> 
>          Stefan
> 
> .

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>

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#262035

On 9/30/23 23:22, hw wrote:
> On Sat, 2023-09-30 at 18:29 -0400, gene heskett wrote:
>> On 9/30/23 13:28, Matthias Böttcher wrote:
>>> sudo dphys-swapfile swapoff
>>> sudo systemctl stop dphys-swapfile.service
>>> sudo systemctl disable dphys-swapfile.service
>>>
>>> .
>> However that did give me a clue about getting rid of zram0, which has
>> been done now, thank you. Now I hope to uncomment the SSD line in fstab.
> 
> Well, zram is the way to go; why would you still use swap partitions
> or swap files instead?  Are you deliberately trying to wear out your
> SSDs or to slow down your computer?
> 
zram is probably the way to go for board with lots of dram. Something 
the pi's don't have. My only pi is an early rpi4b, Claims 2G, shows 
1.8G. I tend to do big things with it. I was first on this ball of rock 
and water to make linuxcnc and that pi, run an 80 yo lathe I converted 
to cnc controls. Teaching that lathe tricks it could not do when it 
shipped out out Chicago circa 1946.

To steal over a gig for zram style swap does not make any sense to me. 
There's compression and decompression involved too I'm told. By putting 
swap on a 10G partition on a 500meg a second SSD, brings big memory into 
the picture, allowing that little card to do big things without running 
out of memory. I've built its own realtime kernels on it is 23 minutes, 
linuxcnc with its docs including some translations ran it 200megs into 
that zram and took nearly 4 hours.  With real swap back on buster, just 
under an hour. Just the English docs are now over 1000 pages of dead 
tree. What we really need are translators. Except for the de stuff, 
other languages are quite incomplete, but this old Iowa farm kid doesn't 
speak anything but English, and doesn't even touch type.

I'm not a "working shop" other than my own product, just a retired bc 
engineer. I basically serve as the canary in the coal mine for linuxcnc, 
keeping that pi up to date with the git master & looking for 
showstoppers. This gets done several times a week, doing a decent job of 
keeping me out of the bars.

> Fedora has it by default since a while, and at first I thought it's a
> very stupid idea.  In practise, I can't be bothered anymore to create
> these annoying swap partitions.  They're only a waste of disc space.
> There haven't been any issues with it, and when the machine runs out
> of memory, using swap partitions or swap files isn't going to fix
> that.

But with zram  taking over half its memory, its into swap and slowing 
down quicker, and plumb out of memory for big jobs, when it could still 
be working fine with bigger, albeit probably slower than zram, swap.

I've no clue how much the zram compression slows it in terms of thru put.

I wiped out the git clone of linuxcnc by re-arranging that SSD 
yesterday, but I'll do another build later today and see how long it 
takes with real swap.

Thank you. Take care & stay well.
> 
> .

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>

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#262047

On Sun 01 Oct 2023 at 04:31:26 (-0400), gene heskett wrote:
> On 9/30/23 23:22, hw wrote:
> > On Sat, 2023-09-30 at 18:29 -0400, gene heskett wrote:

> > > However that did give me a clue about getting rid of zram0, which has
> > > been done now, thank you. Now I hope to uncomment the SSD line in fstab.
> > 
> > Well, zram is the way to go; why would you still use swap partitions
> > or swap files instead?  Are you deliberately trying to wear out your
> > SSDs or to slow down your computer?
> > 
> zram is probably the way to go for board with lots of dram. Something
> the pi's don't have. My only pi is an early rpi4b, Claims 2G, shows
> 1.8G. I tend to do big things with it.

OTOH the Description says:

 "zram-tools uses this module to set up compressed swap space.
  This is useful on systems with low memory or servers
  running a large amount of services with data that's easily swappable
  but that you may wish to swap back fast without sacrificing disk
  bandwidth.

 "By default it allocates 100MB of RAM, you can configure this in
  /etc/default/zramswap."

> To steal over a gig for zram style swap does not make any sense to me.

Did they just copy a Fedora configuration? I've read that this is what
it does.

> > Fedora has it by default since a while, and at first I thought it's a
> > very stupid idea.  In practise, I can't be bothered anymore to create
> > these annoying swap partitions.  They're only a waste of disc space.
> > There haven't been any issues with it, and when the machine runs out
> > of memory, using swap partitions or swap files isn't going to fix
> > that.
> 
> But with zram  taking over half its memory, its into swap and slowing
> down quicker, and plumb out of memory for big jobs, when it could
> still be working fine with bigger, albeit probably slower than zram,
> swap.

I hadn't come across this package before, so I installed it on an idle
laptop. With configuration completely untouched, OOTB, it reports:

  $ free 
                 total        used        free      shared  buff/cache   available
  Mem:        16256864      197692    10999672        1848     5059500    15714244
  Swap:         262140           0      262140
  $ cat /proc/swaps 
  Filename                Type            Size            Used            Priority
  /dev/zram0              partition       262140          0               100
  $ 

Cheers,
David.

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#262070

On Sun, 2023-10-01 at 04:31 -0400, gene heskett wrote:
> On 9/30/23 23:22, hw wrote:
> > On Sat, 2023-09-30 at 18:29 -0400, gene heskett wrote:
> > > On 9/30/23 13:28, Matthias Böttcher wrote:
> > > > sudo dphys-swapfile swapoff
> > > > sudo systemctl stop dphys-swapfile.service
> > > > sudo systemctl disable dphys-swapfile.service
> > > > 
> > > > .
> > > However that did give me a clue about getting rid of zram0, which has
> > > been done now, thank you. Now I hope to uncomment the SSD line in fstab.
> > 
> > Well, zram is the way to go; why would you still use swap partitions
> > or swap files instead?  Are you deliberately trying to wear out your
> > SSDs or to slow down your computer?
> > 
> zram is probably the way to go for board with lots of dram. Something 
> the pi's don't have.

You only need as much RAM as is sufficient for what you're doing.
That's the way to go while having more RAM doesn't hurt much.

Swapping to SSDs is slow.  If it's faster than zram, something must be
wrong.

In an earlier message you're saying RAM isn't an issue.  So why are
you messing with it?

10GB swap on an SSD you're actually tring to use?  Ugh ...  It's maybe
ok for preventing the system from going into some undefined and
undesirable state from running out of memory for instances in which
you're trying to figure out how much RAM you need.  Once you figured
it out, you add sufficent amounts of RAM and use zram.

BTW, how do you prevent breaking the lathe when the pi or the software
fails?  There's things that can go wrong and lathes tend to be rather
powerful tools.  Do you have some device to detect failures and some
kind of break that stops the lathe immediately when something goes
wrong?

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#262081

On 10/1/23 16:01, hw wrote:
> On Sun, 2023-10-01 at 04:31 -0400, gene heskett wrote:
>> On 9/30/23 23:22, hw wrote:
>>> On Sat, 2023-09-30 at 18:29 -0400, gene heskett wrote:
>>>> On 9/30/23 13:28, Matthias Böttcher wrote:
>>>>> sudo dphys-swapfile swapoff
>>>>> sudo systemctl stop dphys-swapfile.service
>>>>> sudo systemctl disable dphys-swapfile.service
>>>>>
>>>>> .
>>>> However that did give me a clue about getting rid of zram0, which has
>>>> been done now, thank you. Now I hope to uncomment the SSD line in fstab.
>>>
>>> Well, zram is the way to go; why would you still use swap partitions
>>> or swap files instead?  Are you deliberately trying to wear out your
>>> SSDs or to slow down your computer?
>>>
>> zram is probably the way to go for board with lots of dram. Something
>> the pi's don't have.
> 
> You only need as much RAM as is sufficient for what you're doing.
> That's the way to go while having more RAM doesn't hurt much.
> 
> Swapping to SSDs is slow.  If it's faster than zram, something must be
> wrong.
> 
> In an earlier message you're saying RAM isn't an issue.  So why are
> you messing with it?
> 
> 10GB swap on an SSD you're actually tring to use?  Ugh ...  It's maybe
> ok for preventing the system from going into some undefined and
> undesirable state from running out of memory for instances in which
> you're trying to figure out how much RAM you need.  Once you figured
> it out, you add sufficent amounts of RAM and use zram.
> 
> BTW, how do you prevent breaking the lathe when the pi or the software
> fails?  There's things that can go wrong and lathes tend to be rather
> powerful tools.  Do you have some device to detect failures and some
> kind of break that stops the lathe immediately when something goes
> wrong?
> 

There are several checks which can stop lcnc in the next millisecond. 
They have been well tested, but have yet to do so while working. I am 
slowly converting all my stepper drivers to closed loop versions, the 
next generation in motors, which have several advantages over std 
steppers. First they control motor power with the magnitude of the 
error, so motors don't run burn your hand hot unless being really 
pushed. 2nd, they get to where lcnc ends them or if they can't get 
there, they'll kill the motor power and advise lcnc of the failure which 
if wired correctly, shuts lcnc down in its tracks a millisecond later. I 
now have 5 of those motors turning things and that failure has yet to 
occur while working.  I guess I'm sold.

Take care & stay well, hm

Cheers, Gene Heskett.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>

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#262110

On 02/10/2023 03:01, hw wrote:
> Once you figured
> it out, you add sufficent amounts of RAM and use zram.

Is it possible for *Pi boards? Even laptops may have soldered RAM with 
no spare slots.

ZRAM may be fast, but if you need, say +2G in comparison to physical RAM 
size, the chance of success is fair in the case of RAM size of 16G. If a 
board has just 2G of RAM then you need to be really lucky to get extra 
2G by compression.

Perhaps Gene's setup is no optimal, but swap on SSD, despite its 
disadvantages, may be an alternative to using a more performant board 
for building of applications.

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