CPU execution in Guest very slow

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ArturVonTirol
Posts: 4
Joined: 16. Nov 2018, 10:13

CPU execution in Guest very slow

Post by ArturVonTirol »

Hello

I am running several Linux Guests on a Windows 10 Host. Now I realized the Guests have very slow CPU execution. I am sure it was diffent some time ago, but do not know the reason or what has changed. I had the new installed 5.2.x version under suspicion and went back to 5.1.28 and then 5.1.38 again. But noting changed.
Running a simple CPU Test using Linux Binary Calculator will take 3 to 4 times longer on the Guest then it does on the Host.
On the Host I tried using Cygwin and also bootet the machine using a live linux. My simple test will take about 11 seconds to run in both aproaches.

On all the Linux guests it will take about 37 seconds!!! And as expected one CPU will be allocated at 100% on the guest and on the host the Intel CPU will be running at maximum frequency.

I tried a brand new linux lite image from osboxes_org and the result was just the same.

The benchmark I am using is simply running the command in a shell:
time echo "scale=4000; a(1)*4" | bc -l

And only to get it right: it's not the Binary Calculator issue disturbing me ;-). The execution of real applications (WebSphere) is very slow too!

vbox log is attached

Thanks,
Artur
Attachments
VBox.log.zip
(15.65 KiB) Downloaded 5 times
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: CPU execution in Guest very slow

Post by mpack »

Never mind that it runs slowly, I'm amazed that this guest runs at all.
00:00:01.904884 Host RAM: 16080MB (15.7GB) total, 3086MB (3.0GB) available
..
00:00:02.038785 RamSize <integer> = 0x00000001d7f00000 (7 917 797 376, 7 551 MB, 7 GB)
..
00:00:01.995320 Guest OS type: 'Linux_64'
00:00:02.038782 NumCPUs <integer> = 0x0000000000000001 (1)
ArturVonTirol
Posts: 4
Joined: 16. Nov 2018, 10:13

Re: CPU execution in Guest very slow

Post by ArturVonTirol »

thankyou, this surely was not the reason - at the time i took the log from (for the post here) there was another really big VM running.
but the Binary Calculator test does not require much memory and the machine had still enough memory.

AND: I had many other tests running this small VM (really nothing inside apart from my bc test) all by itself with plenty of memory on the host with all the same result.

I went further: converted the VDI to VMWare format and created a VMWare VM from it. Runing the my benchmark in WmWare took about 11 seconds!!!!!!!!!! Just as on the host. So definitely this is a VirtualBox issue.
ArturVonTirol
Posts: 4
Joined: 16. Nov 2018, 10:13

Re: CPU execution in Guest very slow

Post by ArturVonTirol »

There is one more thing to mention. I investigated 6 computers (all laptops). Two machines do have the issue - 4 do not have it. All are running Widnows 10 as host.
There must be something special about these machines, but I do not have a clue.

So is the only advice to switch to VMWare?
Martin
Volunteer
Posts: 2560
Joined: 30. May 2007, 18:05
Primary OS: Fedora other
VBox Version: PUEL
Guest OSses: XP, Win7, Win10, Linux, OS/2

Re: CPU execution in Guest very slow

Post by Martin »

Can you try to do a similar test run (start VM, test, shutdown VM) on a "fast" and on a "slow" system and then upload/attach the zipped log files of these runs here?
ArturVonTirol
Posts: 4
Joined: 16. Nov 2018, 10:13

Re: CPU execution in Guest very slow

Post by ArturVonTirol »

good idea - here they are
I recreated on both machines a new VM starting from the linux-lite VDI. With the same settings.
Results of my simple benchmark were again the same 10 seconds vs 37 seconds

Also attached a second version of the logfiles where the timestamps are removed, which makes a diff easier.
Attachments
VBoxLogs.zip
(80.48 KiB) Downloaded 6 times
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