100% CPU in VirtualBox, fixed or not worth it?

[infoagee]

Hi,

I found later versions of 0.4.5c & 0.4.6a cost 100% cpu when run in VirtualBox(5.0), Win7, with grldr on ext2 fs. And I found serveral issues here, like: #89, 2015,12, says: 0.4.5c cost 100% cpu for VirtualBox #118, 2016.06, says: 0.4.5c-2012.06.19 is ok, while later versions make cpu 100% #198, 2019.07, by @steve6375, and @yaya2007 said "I decided to give up".

So, does this means this issue will not be fixed? or already fixed? or even no such bug existed? or no need to fix? or sth else?

[a1ive]

I don't think #198 is related to the bug you reported.

[infoagee]

Maybe. Though I think they are related, but I am not sure.

[infoagee]

I modified several lines of grub4dos-0.4.5c-2015-05-18, and it seemed working properly for my simple case. I am not sure it's buggy or not. At least, according to the changelog mentioned below, it should be buggy for some AMD cpus.

1st, I found an article talking about this phenomenon, and it mentioned HLT instruction: http://wiki.freedos.org/wiki/index.php/VirtualBox_-_Bugs:_High_CPU_usage_of_FreeDOS_machine 2nd, I noticed the changelog lines between 2012-06-19.7z and 2012-10-02.7z, of 0.4.5c, in ChangeLog_GRUB4DOS.txt of source package, and it reads: "removed HLT instructions to satisfy buggy AMDs." last, uncomment "hlt" lines in stage2/asm.S ( 3 lines in total), and build it by ./autogen.sh. Build successfully with CentOS 7 and Ubuntu 16.04 LTS. Doc referred: https://rmprepusb.com/other-useful-articles/how-to-compile-grub4dos-and-grub4dos-utilities/