On Sun, 5 Aug 2012 07:47:49 -0700 Rich Braun <[email protected]> wrote: > As for how it could be possible: CPU performance far exceeds that of > any current I/O. So emulation overhead drops way below the roughly 3% > CPU overhead that I recall measuring. Throw a big RAM cache > underneath your VM, and you can get blazing fast numbers.
Ah-hah! Yes. If you cache I/O then you bypass the trap and emulate latency. You will see similar performance on bare metal. But you did stipulate not caching I/O so as to avoid data loss in case of a power failure. If you take the cache away then performance drops to the disk and controller at which point you should see a small but measurable performance hit on the emulated controller. If you don't then there's probably still some caching going on somewhere. -- Rich P. _______________________________________________ Discuss mailing list [email protected] http://lists.blu.org/mailman/listinfo/discuss
