Okay, specs are:
OS: Linux (debian, gentoo, both the same)
System: i5 520m, 2.40GHz, 4GB RAM
DOSBOX: 0.74, 0.74-2, SVN
I always have used official version of dosbox. This behaviour is everytime, no program but command shell loaded. See the attached dosbox.conf autoexec section. A few mounts, keyboard, done.
It is difficult to catch dosbox with top with screenshot tool. The moment the screenshot is taken, dosbox is already somewhere else in list.
It jumps always between 88% and 100%, sometimes I see 90%, 95%, 100%, but never goes below 88% and most of the time it is near 100%.
I am using a stock dosbox.conf that comes with distro-packages. Just have edited autoexec-section to my needs.
Booting a whole VM like qemu is a waste of time. I usually use dosbox for cross-development on my linux-box. This way I can really easy test:
Makefile contains a "make test" target. This target starts dosbox and the program I am currently working on. This goes within max. 2 seconds.
Does dosemu2 take advantage of KVM/VTx?
Okay, I havent thought to the end. Havin dosbox with KVM will result in a way too fast system. But slowing it down again with "NOPs" would bring a huge efficiency benefit compared to emulating a CPU.
While waiting for the cycle-time to be complete the host-system is free for other tasks.