Nitpicking: htop and # of cpus online about htop HOT 15 CLOSED

@jorgechamorro When a CPU bar is created, it's online/offline status should update in the same interval as CPU percentages. Not doing so would be a bug.

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Please retry with a newer version like 3.3.0. There has been quite a bit of changes since 3.0.5 was released.

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The number of cores is read at startup, but cores that go offline while htop is running should be indicated accordingly.

Thus the question: If you start htop with all CPUs online and put one core offline while htop is running, does the CPU meter show the corresponding core as offline?

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@jorgechamorro

the # of cores displayed properly, unless I close and open it again.

What's the "# of cores" field you are referring to?
Please be precise on which field is displayed wrong. A screenshot can also be helpful on explaining the bug.

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Say there are eight cores and eight cpu bargraphs showing in htop, and in another window I turn off a core, htop keeps displaying eight cores as if nothing had happened. Now, say I'm seeing only seven because I turned off one before launching htop, and I turn that core back on, again, htop keeps displaying only seven cores when in reality there are now eight online.

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Say there are eight cores and eight cpu bargraphs showing in htop, and in another window I turn off a core, htop keeps displaying eight cores as if nothing had happened. Now, say I'm seeing only seven because I turned off one before launching htop, and I turn that core back on, again, htop keeps displaying only seven cores when in reality there are now eight online.

Adjusting the number of bars in the display can ruin the meter layouts the user may have carefully set. I would argue that this is "not a bug".

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Unless hiding offline CPUs is active, all 8 cores (even if some offline) should be displayed; with some of the cores labelled as offline. If that's not the case, this is a bug and should be investigated.

If hiding of offline cores is active, then updating the layout may cause significant flicker if one or more cores are activated/deactivated in quick succession. IIRC there was some discussion about this a while back, when hiding of offline CPUs was implemented. @fasterit ???

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Yes, there is no technical reason for "[w]henever I switch off cores" but playing around. So I see no need for htop to scan the topology every cycle for that niche use case.
/DLange

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Yep, no need to re-scan so often, maybe just once every n secs? That would be great.

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And perhaps behind a flag 're-check # of (active/enabled) cores every [n] secs' ?

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@jorgechamorro Why the "re-check number of cores every n secs" option? It seems like we are tackling the wrong problem. It's unlikely that the "maximum supported CPUs" can be changed for a particular hardware, and the real option we need is "show all offline CPUs" so the meters will allocate space for CPUs that are offline at the moment.

Dynamically adding or removing meter bars can break the layout, which is something we should avoid doing.

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You mean always show all cores even disabled ones, but the disabled ones' bargraph shows 'offline' or something? That of course would be great. But still, then, how often would you check/update the online/offline status of the cores?

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@jorgechamorro When a CPU bar is created, it's online/offline status should update in the same interval as CPU percentages. Not doing so would be a bug.

Ok! But that's not what's happening here. htop --v gives me htop 3.0.5 maybe that's the problem? Thanks.

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I tried with htop 3.2.2 and it does as you say: shows bargraphs for all cores regardless of online state, and marks as 'offline' those that are, and updates as soon as the on/offline state changes. Great! Thanks.

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Ergo, closing.

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