Adam Leventhal's blog

Month: July 2004

This past week at OSCON I’ve spent my time trying to understand open source processes, talking about Solaris, and trying to figure out what OpenSolaris is going to look like.

Learning from Linux

I attended a talk by Greg Kroah-Hartman about Linux kernel development. As we work towards open sourcing Solaris, we’re trying to figure out how to do it right — source control, process, licenses, community etc. As I didn’t know much about how Linux development works, I was hoping to learn from a largely successful open source operating system.

Linux development is built around fiefdoms maintained by folks like Greg. Ordinary folks can contribute to the repositories they maintain (either directly or by proxy based on some sort of Linux-street-cred it seems). Those repositories are then fed up to a combined unstable repository, and from there Linus himself ordains the patches and welcomes them into the circle of linux 2.6.x. This all seemed to make some sense and work alright. That is, until someone asked about firewire support. The answer, “I wouldn’t run firewire — it should build [laughter], but I wouldn’t run it. The discussion then led to Linux testing which it seems is highly ad-hoc and unreliable. IBM and Novell are working on nightly testing runs, but very little exists today in terms of quality control tests or general tests that developers themselves can run before they integrate their changes.

In Solaris, testing can be arduous. Some changes are obvious and can be tested on just on architecture, but others require extensive tests on a variety of SPARC and x86 platforms. And linux supports so many more platforms! I have no idea how a developer working on his x86 box can ever be sure that some seemingly innocuous change hasn’t broken 64-bit PPC (or whatever). Clearly this is something we have to solve for OpenSolaris — reliability and testing are at the core of our DNA in the Solaris kernel group, and we need to not only export that idea to the community, but only some subset of facilities so that contributors can adhere to the same levels of quality.


Later in the day a bunch of us from Solaris met with some open source leaders (I don’t know quite how one earns that title, but that’s what our liaison told us they were). We first told them where we were: Yes, we really are going to open source Solaris; no, we don’t know the license yet; no, we don’t know if it’s going to be GPL compatible; no, we aren’t planning on moving the cool stuff in Solaris over to Linux ourselves; and, no, we do not know what the license is going to be, but we promise to tell you when we do.

We got a lot of helpful suggestions from folks involved with apache and other projects. “Bite sized bugs” sound like a great way to get new people involved with Solaris and contributing code without a huge investment of effort. Documentation, partitioning and documenting that partitioning will all be much more important that we had previously anticipated. We get the message: OpenSolaris will be easy to download, build, and install, and we’ll make sure it’s as easy as possible to get started with development.

The one thing that disappointed me was the lack of knowledge about Solaris 10 — some comment suggested that the members of the panel think Solaris doesn’t really have anything interesting. Fortunately we had the BOF that night…

The Solaris Community

Andy, Bart, Eric and I held a BOF session last night to talk about OpenSolaris and Solaris 10. After satiating the crowd’s curiosity about open sourcing Solaris (no, we don’t know what the license is going to be), we gave some Solaris 10 demonstrations.

Since we were tight on time, I buzzed through the DTrace demo in about 15 minutes touching on the syscall provider, aggregations, the ustack() action, user-land tracing with the pid provider and kernel tracing with the fbt provider. Whew. Then came the questions — some of the audience members had used DTrace, others had heard of it; almost everyone had a question. When I demo DTrace, there’s always this great moment of epiphany that people go through. I can see it on their faces. After the initial demo they look like people who just got off a roller coaster — windblown and trying to understand what just happened, but there’s always this moment, this ah-ha moment, when something — the answer to a question, an additional example, an anecdote — sparks them into understanding. It’s great to see someone suddenly sit up in her chair and start nodding vigorously at every new site I point out in the DTrace guided tour.

My personal favorite piece of input about OpenSolaris was someone’s claim that six months after Solaris goes open source there will be a port to PowerBook hardware. If that’s true then everyone in the Solaris kernel group is going to have PowerBooks in 6 months plus a day.

Before the BOF, I was worried that we might not find our community for open source Solaris. Not only was there a good crowd at the BOF, but they were interested and impressed. That’s our community, and those are the people who are going to be contributing to OpenSolaris. And I can’t wait for it to happen.

Two members of the ZFS team have joined the blogging fray. Check out Matt Ahrens‘s and Val Henson‘s weblogs.

For the unintiated, ZFS is the brand new file system that’s going to be in Solaris 10. ZFS is incredibly fast, reliable, and easy to manage. I recently moved my home directory from out UFS file server to an experimental ZFS file server. Opening my (extensive) mail spool went from 20 seconds to 3; doing an ls(1) sped up by more than a factor of two in my home directory; and the repository of crash dumps I keep went from 40G to 4G. This is really cool technology both under the hood and from the point of view of users and administrators — stay tuned to their weblogs for all the details.

eWEEK has an article on DTrace. The analysis of DTrace is pretty accurate, but they refer opaquely to Bryan and me as “Sun officials”. I’m looking forward to their in-depth comparison of DTrace and DProbes…

This afternoon, I’m leaving for OSCON (easily confused with the bi-mon-sci-fi-con). Here in Solaris Kernel Development we’ve been talking a bunch about the impending open sourcing of Solaris and what that’s going to look like. I’m very excited about OpenSolaris itself, and I’m looking forward to talking to folks at OSCON to hear what they think.

The part they’re going to find most surprising is that this is for real. Within a year or two, there are going to be people from outside of Sun contributing to Solaris. Period. It’s going to be a little scary, but I’m excited about the possibilities of what this might mean for Solaris (my dream of Solaris on my PowerBook might even come true).

We’re holding a BOF session on Thursday at 9pm. So come by if you want to talk to Andy, Eric, Bart or me about the cool stuff in Solaris 10 or about open sourcing Solaris. Stay for the free (as in beer) beer.

I haven’t been as prolific a blog writer as I like for the last few days because I’ve been working morning, noon, and night on some pretty cool new stuff for DTrace. Here’s a teaser, I promise I’ll give you more later when I have it all working:

bash-2.05b# dtrace -l -n plockstat100694:::
ID     PROVIDER            MODULE                        FUNCTION NAME
37394 plockstat694                mutex_lock_queue mutex-block
37395 plockstat694                     rwlock_lock rw-block
37396 plockstat694                 __mutex_trylock mutex-acquire
37397 plockstat694                  __mutex_unlock mutex-release
37398 plockstat694           mutex_unlock_internal mutex-release
37399 plockstat694          mutex_trylock_adaptive mutex-spin
37400 plockstat694                     rwlock_lock rw-block
37401 plockstat694                 cond_wait_queue mutex-acquire
37402 plockstat694           _pthread_spin_trylock mutex-acquire
37403 plockstat694                     lmutex_lock mutex-acquire
37404 plockstat694                 __mutex_trylock mutex-acquire
37405 plockstat694                 mutex_lock_impl mutex-acquire
37406 plockstat694               fast_process_lock mutex-acquire

In case you need a hint, note that plockstat rhymes with lockstat(1m)

Another linker alien has joing the b.s.c. fray. Mike Walker already has some useful stuff about shared libraries that you should check out. If you have linker questions, do what I do: ask Mike.

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