It’s turned off and on by the sysctl machdep.isolated_user_pmap – and defaults to on for Intel CPUs. Buildworld tests show about a 4-5% performance hit, but that’s only one form of activity, measured, so there will surely be other effects.
Note that Spectre is not mitigated by this commit series, and as I understand it, cannot be realistically fixed in software.
Update: Matthew Dillon posted a summary to users@.
Update 2: He told us so.
SSH in DragonFly 5, by default, does not make a password authentication request on outgoing ssh sessions. You can manually add the option or change the config. Or use public keys, which is really the best idea if at all possible.
DragonFly 4.8 has been updated to 4.8.1, bringing in a lot of small fixes. Improved Intel video support and the virtio_scsi driver will be of most interest, I think. The 4.8.1 tag commit has all the details. You can update the normal way, and if you need an install image, I’ve uploaded them and they should appear at your local mirror.
Recent changes for virtual machine support and the new powerd utility have been rolled into the release branch for DragonFly. They’ll probably be in the next point release, or you can rebuild a release machine now for immediate access.
Also mentioned in the update from Matthew Dillon, DragonFly-master users should upgrade carefully as DragonFly migrates to using LibreSSL in base, and dports-based LibreSSL in dports.
Because this always happens just after I create a DragonFly release, there’s a new version of OpenSSL. However, this is for version 1.0.2. 1.0.1 is what’s in the release, and it’s supported through the end of the year.
OpenSSH has a major version bump in DragonFly, to 7.3p1. This means some features – specifically patches for High Performance Networking – are no longer there, and you’ll get an error if your config file requires them. Either remove the options from your config, or install OpenSSH from dports.
I’m a bit late on this, but: If you are using DragonFly-current, you will need to rebuild world. If you are on 4.4, this won’t matter until you go to 4.6, and you’d be rebuilding world and kernel for that anyway.
(4.6 will probably be tagged this weekend.)
If you are running bleeding-edge DragonFly, Sepherosa Ziehau has made some networking changes that both reduce CPU usage in high-traffic situations and change some underlying network structures. This means a full buildworld is needed on your next update.
If you’re using DragonFly 4.4.x or older, you are unaffected.
That’s a pretty cryptic headline, isn’t it? John Marino has ‘privatized’ several libraries in DragonFly, so that they can’t get included involuntarily as part of a port build. That may mean you will need to perform a full rebuild of your system if you are tracking DragonFly-current.
(This is the way to fix ‘system’ languages like Perl was in FreeBSD 4.x – keep them clearly separate from the port version. It’s about a decade too late for that idea to work out, though.)
Note: keep in mind this is a client bug – it’s an information leak when you as a client connect out to somewhere else. A server, as an endpoint, is not affected.
If you are using bleeding-edge DragonFly (4.3) on a machine with Intel video, the i915 module has been renamed. This means you will probably need to rebuild xf86-video-intel from source to have it match. There should be a matching binary package soon.
If you are on DragonFly 4.2, this does not affect you.
It has finally happened: There’s no more IPv4 addresses left to allocate, at least for ARIN – and that’s going to affect most people reading this. Ask your ISP for IPv6 access. The next step is being forced to implement either wonky 6to4 mappings, or just plain IPv6 networks.