On Sun, 12 Aug 2018 15:52:44 +0100 Sad Clouds <cryintotheblue...@gmail.com> wrote:
> On Sat, 11 Aug 2018 18:09:15 +0200 > Martin Husemann <mar...@duskware.de> wrote: > > > On Sat, Aug 11, 2018 at 04:02:44PM +0100, Sad Clouds wrote: > > > Hi, so you're saying that with ucb_direct read/write on mounted > > > file system should also speed things up compared to NetBSD-8? I > > > see terrible I/O performance with NetBSD running as a VM on a > > > VirtualBox, just reading/writing regular files is quite slow > > > compared to Linux VMs on the same hardware. I've never been able > > > to figure out the reasons for it, maybe Linux has better > > > integration with VirtualBox and better optimisations. > > > > We had a similar discussion on some list a while back and I did some > > timings. My values were close to the ones others cited for Linux and > > others said their NetBSD timings were a lot worse than mine. > > > > I use SATA and NVMe emulations in virtual box, and mount all > > filesystems on the emulated SATA drives with "log". > > > > Don't think I had to tweak anything special on the host or in > > virtual box. > > > > Martin > > Yes we did, however I only get about 50 MB/sec on a NetBSD VM, file > system mounted with "log", while Debian physical host that runs > VirtualBox-5.2.16 is capable of around 800 MB/sec: > > $ dd if=/dev/zero of=out bs=1M count=10000 conv=fsync > 10000+0 records in > 10000+0 records out > 10485760000 bytes (10 GB, 9.8 GiB) copied, 13.0382 s, 804 MB/s > > Yes there will be some virtualisation overhead, but not this much. I > started comparing raw device I/O on NetBSD VM and got around 200 > MB/sec, but that is still somewhat less than what I was expecting. > > But if I boot NetBSD on this physical hardware from a second disk and > read raw device that contains Debian on RAID0 SSDs, I get around 890 > MB/sec. So there is something weird about running NetBSD in a > VirtualBox. Linux VMs don't seem to have such issues. There are a few > other things I'm going to try, but at the moment I just don't know > what causes this. OK, I cloned NetBSD VM, kept everything the same, but installed Debian with XFS file system. $ dd if=/dev/zero of=out bs=1M count=10000 conv=fsync this gives 682 MB/sec which is what I would normally expect
