Sepherosa Ziehau has continued his quest of making large-scale data transmission on DragonFly effortless; his latest change has cut the kqueue contention rate by two-thirds when dealing with a connection rate of nearly 400,000 connections per second. Note that’s number of connections, without even tracking the bandwidth used by each.
Bill Yuan has added ‘ipfwsync’ to ipfw3 in DragonFly. As you may expect from the name, it’s a way to sync ipfw3 configurations across multiple devices.
Welcome the newest DragonFly committer: Bill Yuan. His ipfw3 work has been going on for a while.
If you have a Broadwell system, the drm.i915.enable_execlists tunable added by Imre Vadász may keep your system stable. (thanks, zach on EFNet #dragonflybsd)
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.)
This has no effect on the actual operation of DragonFly, but it makes me feel better that it’s done: Rimvydas Jasinskas has gone through DragonFly source and removed the unnecessary 3rd BSD license clause, which is no longer needed.
Please welcome DragonFly’s newest committer: Rimvydas Jasinskas. He’s already done some adding and removing, and he’s been making a ton of dports changes for some time.
A number of people have reported problems with qemu and DragonFly, both running locally and on a host. It turns out to be a problem with the getcontext(), setcontext(), and swapcontext() functions, but Matthew Dillon fixed it in a way that doesn’t affect performance very much.
That apparently wasn’t good enough, so he added _quick versions of those same functions, so it became not just a fix, but an improvement.
In related qemu news: qemu-devel can use vknetd similar to a vkernel, now.
Hammer now defaults to ‘noatime’, meaning the date and time of last access are not updated on every file action. Note that creation and modification date and time are still recorded. This will help with speed and disk activity.
This may cause a problem with any software expecting this to change – mutt, possibly? We will find out. This change was done after the 4.4 branch, so it’s not in the current release of DragonFly.
I am taking this moment away from my significant backlog of things to post to note that there have been a lot of games fixes in DPorts lately. Thanks to Rimvydas, many small bugs that kept games from compiling on DragonFly are now fixed. The easiest way to see is to look at the commits from December 8th and back, but the best way is to pick one and play.
If you are running DragonFly-master (i.e. 4.5), and you have a system between these two updates (roughly between November 27th and now), please rebuild your kernel to avoid a TCP bug.
I have a huge backlog of things to post, so this is originating from the 17th: Matthew Dillon has been working for some time on hardlinks and Hammer 2. Hardlinks are the same file, presented in multiple places. This can be a problem when your filesystem keeps infinite, writable snapshots. The solution he just commited is called ‘xlink’ and the commit message has details.
The default linker in DragonFly has been switched to gold, the newer version of ld. (get it, go-ld?) It’s faster, cleaner, going by the commit message. It’s possible to switch back to the old one if needed. This predates the recent branch for 4.4, so it will be default in the release, too.
Imre Vadász fixed top so that hitting ‘c’ filters displayed processes by command name. I am mentioning this not because it’s a huge change, but because I forget about all the interactive elements that are possible with top.
Does that count as alliteration? Anyway, Matthew Dillon has increased the size of the starting window in TCP. If you are on a higher-latency link and/or fetching lots of small files, you should notice better performance.
The disk scheduler apparatus in DragonFly has been removed. This may not affect you much, since alternate scheduling setups were never utilized much with it. It may fix some rare Hammer cleanup issues, though, and you may need to adjust your custom kernel config, if you have one.
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.
I think at this point, Sepherosa Ziehau is able to improve the DragonFly network stack by just standing near his computer and concentrating for a few minutes. For example, he’s unearthed another improvement to connect rate/reduction of CPU usage.