Questions about proced

Questions about proced

[Rahguzar]

I have a question about proced:

1) The pmem construct in proced corresponds to the percentage of memory used
by a process. However the total memory used for this calculation
includes swap. Is it possible to limit this to just RAM?

2) The pcpu construct displays the percentage of cpu used by a process.
However it seems like it uses a very long interval to calculate this
percentage. So often processes which are basically idle now show up at
the top when sorting the processes by pcpu and I can see the cpu used by
them decaying slowly. Is it possible to use a shorter interval for pcpu?

Thanks,
Rahguzar

Re: Questions about proced

[Eli Zaretskii]

> From: Rahguzar <rahguzar@zohomail.eu>
> Date: Sat, 06 Apr 2024 11:57:09 +0200
> 
> I have a question about proced:
> 
> 1) The pmem construct in proced corresponds to the percentage of memory used
> by a process. However the total memory used for this calculation
> includes swap. Is it possible to limit this to just RAM?

I'm not sure I understand: you do have rss in the attributes, and I
presume that the amount of physical RAM in the system is well known,
so why is it a problem?

> 2) The pcpu construct displays the percentage of cpu used by a process.
> However it seems like it uses a very long interval to calculate this
> percentage. So often processes which are basically idle now show up at
> the top when sorting the processes by pcpu and I can see the cpu used by
> them decaying slowly. Is it possible to use a shorter interval for pcpu?

AFAIK, this is calculated by the OS, not by Emacs.

Re: Questions about proced

[Rahguzar]

Hi Eli,

> I'm not sure I understand: you do have rss in the attributes, and I
> presume that the amount of physical RAM in the system is well known,
> so why is it a problem?

It is a minor problem but I actually don't understand how proced is
calculating the percentage. If I compare the percentage memory value
from proced with that of top I see that top show a value 4 times that of
proced. Before noticing this I though it was due to proced including
swap but the amount swap is half the amount of ram so I would have
expected the factor to be 1.5. Other programs also show values very
similar to top. The problem is that if I don't remember this fact, I
don't catch the high memory usage.

> > 2) The pcpu construct displays the percentage of cpu used by a process.
> > However it seems like it uses a very long interval to calculate this
> > percentage. So often processes which are basically idle now show up at
> > the top when sorting the processes by pcpu and I can see the cpu used by
> > them decaying slowly. Is it possible to use a shorter interval for pcpu?

> AFAIK, this is calculated by the OS, not by Emacs.

Comparing with top, I notice that value is top changes much more quickly
compared to proced and better reflects the current load. The amount of
total cpu time used by a process is identical between top and proced so
I had assumed that they differed by how the calculated the current load.

Thanks,
Rahguzar

Re: Questions about proced

[Eli Zaretskii]

> From: Rahguzar <rahguzar@zohomail.eu>
> Cc: help-gnu-emacs@gnu.org
> Date: Sun, 07 Apr 2024 17:33:50 +0200
> 
> Hi Eli,
> 
> > I'm not sure I understand: you do have rss in the attributes, and I
> > presume that the amount of physical RAM in the system is well known,
> > so why is it a problem?
> 
> It is a minor problem but I actually don't understand how proced is
> calculating the percentage. If I compare the percentage memory value
> from proced with that of top I see that top show a value 4 times that of
> proced. Before noticing this I though it was due to proced including
> swap but the amount swap is half the amount of ram so I would have
> expected the factor to be 1.5. Other programs also show values very
> similar to top. The problem is that if I don't remember this fact, I
> don't catch the high memory usage.

You have the sources (in sysdep.c) of what Emacs does, so you can just
look there, and then consult the various system documentation.  AFAIR,
the %Mem column should show the percentage of the physical RAM that
the process's RSS (resident set) takes.  That's what I see on 2
different systems, one MS-Windows, the other GNU/Linux.  On the latter
I compared with 'top', and it shows the same value.  So I don't think
I understand why you see something different.

> > > 2) The pcpu construct displays the percentage of cpu used by a process.
> > > However it seems like it uses a very long interval to calculate this
> > > percentage. So often processes which are basically idle now show up at
> > > the top when sorting the processes by pcpu and I can see the cpu used by
> > > them decaying slowly. Is it possible to use a shorter interval for pcpu?
> 
> > AFAIK, this is calculated by the OS, not by Emacs.
> 
> Comparing with top, I notice that value is top changes much more quickly
> compared to proced and better reflects the current load. The amount of
> total cpu time used by a process is identical between top and proced so
> I had assumed that they differed by how the calculated the current load.

You need to tell more details, like which process you are looking at
in the list (better not be the Emacs process which shows the Proced
display, for obvious reasons), whether you enabled auto-update in
Proced and with what update interval, etc. etc.