06 August 2014

LL, it's time for 64 bits

The latest viewer statistics are out. There are no real surprises in them; they continue trends we've seen for quite a while now. Firestorm is still by far and away the most widely used viewer on Second Life. There are still substantial numbers of users on older viewer releases, but the usage of non-SSA-capable viewers is low enough that they don't show up in the statistics at all. Pretty much all of the viewers now in use are at least capable of rendering materials, as well (though many users still leave Advanced Lighting Model turned off for performance reasons).

Two facts caught my eye this time around:

For the last two releases of Firestorm (4.6.1 and 4.6.5), there are more users of 64-bit versions than 32-bit versions.

The crash rates for those 64-bit versions are just over half those of the 32-bit versions. Not only that, but the session disconnect rate (defined as the session ending without an explicit logout by the user and without crashing) for 64-bit 4.6.1 is the only one for any Firestorm version, and only one of two for any viewer version, that's below 10%. (The other is 64-bit Singularity 1.8.5, which crashed more often than Firestorm but disconnected less often for other reasons.)

In fact, 64-bit Firestorm crashes less often than any other graphical viewer - and the difference is dramatic: for 4.6.5, it's 6.11% as opposed to 11.30% for the 32-bit version, itself one of the lowest crash rates measured.

(At this point, I have to issue the obligatory grumble about how even a 6% crash rate is horrible to one with my background in mainframe computing, where that kind of problem rate would get someone fired. We've grown to accept crappy computing in general, and that's a bug.)

This tells me one thing: It's time for LL to quit stalling and embrace 64 bits.

64-bit viewers are more stable, and from the reports we get from users, they perform at least as well as, if not better than, the 32-bit equivalents. The end result is a better user experience. It's not universal, but it's quite widespread.

The biggest hold-up in the move to 64 bits is the Havok library. LL distributes that to qualified TPV developers in object form only, and only in a 32-bit version. That means that the Havok version of Firestorm can only be built as a 32-bit program. This only matters to people who make mesh content, or to people who need to see the pathfinding navigation mesh on a sim; there probably aren't many of the latter, but there are lots and lots of the former, and they're people that the Lab actively courts.

What's more, the kind of professional content creator that's taking over SL commerce almost always has the latest, most powerful tools ready to hand - and those tools are 64-bit. They make full use of the power. To stick them with a 32-bit viewer is a bit backward.

The reason that 64-bit viewers are more stable almost certainly has to do with the viewer's memory usage. For at least as long as I've been working on the viewers, they've been plagued with memory leaks: the program allocates memory and never releases it, which reduces the total amount of memory available. When it can't allocate any more, bad things happen. The Lab has been chasing them for years, with at least two major pushes to stamp them out, and yet they're still prevalent. In their defense, the viewer is complex enough that finding and fixing them all will probably never happen. There's just too much code there.

In a 32-bit viewer, the amount of memory one program can use is limited to, at best, 4 GB - and on Windows, it's more like 2.5 GB. A 64-bit viewer can theoretically access up to 256 TB of memory. (Current implementations of the x86_64 architecture have a 48-bit virtual address.) That's effectively infinite.

To borrow a line, "Memory? Leak all you want. We'll make more."

It's getting hard to buy a computer these days that doesn't handle 64-bit programs. Even the lowest-end hardware is 64-bit capable, and is more often than not equipped with a 64-bit version of Windows. Every Mac made in the last 5 years - more importantly, every Mac that's supported by LL and current versions of Firestorm - can run a 64-bit program. Most Linux systems can, as well.

It's time for LL to join the 2010s. TPV developers have done nearly all of the work. I'm sure we'll happily help LL do the rest. Oz is publicly committed to making sure SL gets as much technical goodness as it can.

What are you waiting for, LL?