rv's techblog: some kind of blog

Earlier this morning I integrated changes into ON to decouple the lbolt and lbolt64 variables from clock() as part of the Tickless Kernel project. Here's the heads-up message that followed. Please let me know if you run into any issues or have questions about this change. A follow up post will describe the changes in more detail.

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With the integration of

PSARC/2009/396 Tickless Kernel Architecture / lbolt decoupling
6860030 tickless clock requires a clock() decoupled lbolt / lbolt64

the lbolt and lbolt64 variables have been removed from the system, and the service historically provided by them replaced with the ddi_get_lbolt(9F) and ddi_get_lbolt64(9F) routines. These two functions should be used from now on to get a clock tick based time reference.

This push also introduces the cv_reltimedwait(9F) and cv_reltimedwait_sig(9F) DDI interfaces, which are analogous to the existing cv_timedwait(9F) and cv_timedwait_sig(9F), but take a relative timeout argument instead of an absolute one, and a time resolution argument to specify how accurately the timeout must expire (if it can be anticipated or deferred by the given time unit). These two new interfaces help reduce redundant uses of lbolt in various timed wait consumers. The condvar(9F) man page is being updated with the details, there's an updated version available on our project page[1].

We have, and will continue to work with ISVs and RPE to identify third party modules that improperly reference the lbolt variables and will need to be updated for this CR. We've also identified a handful of references to them in non-ON consolidations and have worked with the appropriate teams to fix them, with ge(7D) being the only outstanding known case (see 6878074).

Please send questions to tickless-dev@opensolaris.org, bugs to solaris/kernel/time and myself. More information on our project page[1] and our PSARC case[2].

[1] http://hub.opensolaris.org/bin/view/Project+tickless/
[2] http://arc.opensolaris.org/caselog/PSARC/2009/396

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Thanks to everyone who contributed to this project. On to the next one!

Quick post on this, I'm pretty sure more people run into the same problem.. Usually the first thing I do after opening a new gnome-terminal is resizing so it doesn't overlap over others or vice-versa. Or if I have a big screen, or know that I'll need really long terminals (or tall ones) and so on.. Anyway, resizing all the time becomes kinda annoying, so I've added the following option to the gnome-panel icon for opening a new terminal:

gnome-terminal --geometry=80x52

Last week I populated the ptop-gtk repository, which holds a Gtk based interface for PowerTOP I've been developing over the last couple of months on my spare time. This new interface is enabled with the -G command line option, and it accepts all the existing options.

The motivation for the new interface is quite simple: increase the density of information displayed to the user. The current curses based interface is very limiting as far as that goes - not to mention a pita to maintain. Yes, it looks pretty, but looks aren't everything ;). I personally think we can take a few generally simple steps with various tools to enhance user experience.

The first tab simply shows what you already get with the current interface, allowing more information than the latter. The second tab displays moving area graphs for idle and frequency states, and a graph for the event report.

A couple of screenshots:

This is still in early development, I've been pushing it along as time allows. I'm writing a Gtk widget for periodic graphs, which is extended by another widget for DTrace based graphs. These widgets allow a very simple plug and play into DTrace consumers, just instantiate one, point the it to the data and it will do the job.

There a number of simple bugs that need to be fixed, but it's a relatively good start. I don't know when it will be ready for putback into snv, like I said, it needs work and it's not a very high priority at the moment. On the same subject, I'm not sure Gtk should be a dependency for ON builds, maybe the right place for this is in another consolidation. I don't know yet.

As always, questions/comments/suggestions are more than welcome.

Enjoy !

The San Francisco OpenSolaris User Group is meeting next Monday (the 27th) at a new location, and starting to hold technical talks. Here's the lineup for this one:

• OpenSolaris.org Overview (Content/OGB/BootCamp Summary) (Michelle Olson)
• Installing OSOL on laptop (dual-boot/Vxm/VirtualBox) (Luc Suryo)
• OpenSolaris and Power Management (Rafael Vanoni)
• How SongBird is put together--for Dummies (Steve Lau)

A couple of months ago I proposed that we start having technical talks and promoting the meetings in different channels. Between all members, I'm sure we can make a reasonable amount of noise around the Bay Area. Anyway, I sent invitations to the SFLUG and JUG (thanks to the leaders of both groups for spreading the word), so hopefully we'll be able to keep this up and grow the group meeting by meeting.

If you're in the area next week, we're meeting at Outspark, on 660 3rd Street San Francisco, 3rd floor Suite #302, near the Borders bookstore. The tech talks should be around 10-15 minutes each, lightning talk style. We're going for drinks and food afterwards.

Thanks to Luc for hosting the meeting.

Ah! If you plan on attending, please rsvp @ our MeetUp page.

The tickless project team is having it's first weekly meeting tomorrow at 10:30 PST. We'll record it and post it to the project page later this week. If you're interested in it, here's the dial-in info and agenda:

Concall|: (866) 651-9314
Participant code: 6160454

Agenda:
- Status & Issues
- lbolt (Rafael)
- tick accounting (Madhavan / Sasha)
- idle system timeout optimizations (Anup)
- clock breakup (esaxe)

The FISL 10 committee started announcing the list of talks that were accepted for this year's Forum. For those who never heard of it, FISL is the International Free Software Forum. Takes place in Porto Alegre, Brazil, every year usually at the end of April, moved up a couple of months this year. It's the biggest FOSS event in Latin America, third in the world last I heard.

I submitted four talks: two on DTrace (for the sysadmin and developer tools tracks), one on OpenSolaris called 'OpenSolaris in 45 Minutes', which is an updated version of the talk I have at the Ontario Linux Fest last year (can't believe it's been almost eight months already), and one on the scheduler, which is the one that got accepted. FISL is known for not accepting more than one talk per speaker.

Although I'm very excited about doing this talk, I was actually hoping/expecting that one of the DTrace talks would be accepted since it's a more recent/new/trendy subject. DTrace is not very well known in Brazil, we still have to overcome more basic adoption problems, maybe that explains it. But having used it on a daily basis for the last couple of years, it's hard to imagine people developing and running their systems without it. Maybe I'm lacking some perspective here, but I was hoping to be able to demonstrate DTrace to a large audience - which will happen anyway, at the floor, one small group of people at a time as it always does.

Another thing that was interesting is that all four talks got really good reviews and comments. Which again proves that people are still open to OpenSolaris as an alternative to other OSes. But the current community growth rate and activity in BR show that we are not taking advantage of that. I've been thinking about this for a good amount of time, and the only answer I can think of is knowledge. I think we as a community need to promote more technical events in Brazil, much like the Front Rage OSUG in the US, or the Tokyo OSUG, or other active OSUGs we always read about. Disseminating knowledge, I think, is the best way to grow our community.

To that end, the Porto Alegre OSUG is doing a DTrace Workshop on June 1st, for the 2009.06 launch. I think it would be much more effective if all the group members participating in FISL were fluent in DTrace, or ZFS, or Zones, .. We're also having a few other events throughout the month, as well as an OpenSolaris Tour just before FISL. Should be fun.

Anyway, if you're making your way down to FISL this year, please stop by and say hi. We'll be easy to spot.