I think some of the mystery is due to my not exploring enough. As I said, I have two windows open when I am doing the test: the Pharo 8 welcome window and a playground which is opened on a cache file. ��I have now found that what happens depends on which is on top. If the welcome window is on top, the CPU usage is zero; if the playground is on top, CPU usage is about 3%, and stays at that even though I provide no input. The implication is that, when a playground is the active window, it is constantly doing something, presumably polling to see if the user is providing input. This did not seem to happen with a similar test on Pharo 6; even though a playground was on top, the CPU usage dropped to zero when I became inactive.
As I said, it���s not a problem, just a puzzle ��� but I would still like to know why.
Peter Kenny
From: Pharo-users <pharo-users-bounces@lists.pharo.org> On Behalf Of Tim Mackinnon
Sent: 11 April 2020 12:42
To: Any question about pharo is welcome <pharo-users@lists.pharo.org>
Subject: Re: [Pharo-users] Pharo 8: What is the VM doing when I am doing nothing?
Hi Peter - I had understood that this always a problem as Morphic is always polling for events (so am surprised you found an image where it���s not happening). I believe that recent work has almost got to a point where this can be resolved - there were some recent status reports on this, and maybe it might get into pharo9?
I���m sure someone has a much better explanation for you - and an explanation of what���s involved to fix it (I guess you have to block the event loop somehow so it waits vs polls).
Tim
On Sat, 11 Apr 2020, at 12:27 PM, PBKResearch wrote:
Hello. I have noticed a curiosity when I am running Pharo 8 on Windows 10. I am in the habit of leaving the Task Manager open when I am working, and it seems that Pharo 8 is using the CPU when I am doing nothing. When the image ��� which is exactly as first loaded, with only the welcome window visible ��� is loaded, CPU consumption is zero. I open a playground, get a list of recent files from the playground cache, open one of the files but do nothing with it; the CPU activity is constantly changing within the range 2.5% - 3.5%. After 5 mins of no Pharo activity by me, the CPU is still in the same range.
I reloaded an earlier image, which is Moose Suite 6.1 (Pharo 6) and opened a playground in the same way. After a few seconds, the CPU usage dropped to zero. This activity is a feature of the newest versions only.
It���s obviously not a major problem, but I would like to know, if just out of curiosity.
Thanks for any help.
Peter Kenny
My Pharo 8 details:
Build information: Pharo-8.0.0+build.1124.sha.0932da82f08175e906b0e2a8052120c823374e9f (32 Bit)
Installed from Pharo Launcher on 8 Apr 2020
VM details:
CoInterpreter * VMMaker-CompatibleUserName.1577968628 uuid: d729bf66-2ea7-5a6d-b1eb-fc005785636d Jan 3 2020
StackToRegisterMappingCogit * VMMaker-CompatibleUserName.1577968628 uuid: d729bf66-2ea7-5a6d-b1eb-fc005785636d Jan 3 2020
VM: 201911290039-dev-7 admin@MacBook-Pro-de-admin.local:dev/Pharo/git-repos/pharo-vm/repo Date: Thu Nov 28 21:39:57 2019 CommitHash: 9b6bd16d3 Plugins: 201911290039-dev-7 admin@MacBook-Pro-de-admin.local:dev/Pharo/git-repos/pharo-vm/repo