Older blog entries for rml (starting at number 27)

kernel

Fix scheduler bugs. One more fix pending. Poop.

Apple

Damn I love this Apple. Both the PowerBook and the underlying operating system are a pleasure.

So Apple finally unveiled the G5. 64-bit. Sick HyperTransport interconnect. Half clock speed system bus. Currently up to 2GHz. Runs dual. Amazing SPECfp and - more importantly - great SPECint. Way to go, Apple.

SPECint vs. SPECfp

Speaking of SPEC scores... I see a lot of people on slashdot and elsewhere exclaiming how amazing the SPECfp numbers are for their favorite architecture. Wild claims like SPECfp is all that matters. What crack are these people on? I do not deny for one moment that SPECfp is important, especially for scientific computationally-intensive applications. For example, if I were designing a cluster for physics research, I would pay a lot of attention to SPECfp numbers. I would look at chips like Alpha and POWER and even IA-64 with good SPECfp numbers. But the vast majority of users - and I am talking nearly all desktop, server, embedded, and even many computational powerhouses - are much more dependent on SPECint numbers.

Look at x86. It has awful floating point performance but (with its high clock speeds) excellent integer performance. And, guess what? It performs best at the stuff people care about. So I think some of us need a reality check. For most uses, SPECint is what matters.

schedutils

schedutils 1.3.0 was released last Thursday. Nothing too special. Mostly build fixes and cleanup, to help get schedutils working in Red Hat Rawhide (yay).

preemptive kernel

Despite 2.5 running so amazingly well, and coming out-of-the-box with a preemptive kernel and tons of sweet low latency enhancements, demand for a preempt-kernel patch for 2.4 is unfortunately high enough that I released a patch for 2.4.21 today.

It fixed an awful lot of bugs, both existing preempt-unsafe code and some new things that cropped up in the longish 2.4.21 development cycle. I recommend an upgrade.

Even better, of course, I recommend an upgrade to 2.5. ;)

Apple, PowerBooks, Mac OS X, and Lupus

So I have been contemplating a laptop upgrade for some time, and eyeing an IBM X31 (a nice lightweight Centrino machine). Screw all that.

I got an Apple PowerBook G4 15".

What can I say? It is an amazingly well designed machine and Mac OS X is (brace yourself) really damn nice. Of course, I run many of the usual Unix applications so I am not in a totally foreign land. It is really an amazingly well put together system, from the hardware up through the software. Stuff just works.

In the past, I have said a lot of good things about GNOME. I strongly believe the Windows interface is junk; it is confusing, ugly, and stupid. I really think GNOME has made a lot of advances and is a very powerful, well thought out, intelligently designed system. That said, there are a few things GNOME can learn from Mac OS X. I see jdub has mentioned this in recent postings. A lot of it is just refinement... but Aqua does impress me.

I have to say the battery life (~3.5 hours on average I would guess) and the suspend/wake up time (mere seconds; and the battery lasts days if not at least a week while suspended).

I have not used anything but Linux for many years now, so it is a nice change to have another machine to play with. Nothing demands my love like Linux, of course ;)

procps

Finally released procps 2.0.13. It includes Red Hat's NPTL enhancements plus other optimizations, bug fixes and cleanups. Please give it a whirl, especially if you are using 2.5.

2.6 Kernel

Looks like 2.6-pre is coming soon. Hooray. For those who have not yet tried it out, I highly recommend it. It has been fairly stable for some time, and we have never had any awful hard drive eating problems or any mess like that.

Falconer

Two weekends ago was the SNL season finale and it featured a rather funny Falconer.

Bay Area

So I am out in the Bay Area again for a few months. The weather sure beats Florida.

Rejoice

There was a new Falconer on Saturday Night Live last night.

schedutils

Released schedutils 1.2.0. Mostly minor bugfixes and cleanups, although also the demise of irqset(1) (what did that have to do with scheduling?) and lsrt(1) (all of the same features, and more, are now in procps).

So, what is in schedutils? taskset(1), a utility for manipulating task CPU affinity (setting it, retrieving it, and launching a new task with an initial given affinity mask) and chrt(1), a utility for manipulating both scheduling priority and policy (also setting them, retrieving them, and launching a new task with a given priority and policy).

Source tarball as well as source and i386 RPM packages built against Red Hat 9 are available.

Java

Man, Java.HasQuality(Quality.Taste.Gross). 'Nuff said.
Gimme c->quality = TASTEFUL anyday.

OLS

Ack! OLS paper is due soonish.

Centrino

I like the design of the chip. More specifically, I like the IBM X31. Maybe some day soon?

64-bit dev_t
Finally got a 64-bit dev_t in 2.5-mm. It looks like 64-bits (and not 32-bits with a 20:12 or 16:16 split) is going to be the way we go. With 64-bits, we will do a 32:32 major:minor split. Plenty of room and I think people will be satisfied. It is good someone (aeb) is putting in the work and others are happy with the progress. Linus seems to agree with Andries's code and no one else is raising a fight. Andrew ought to push it to Linus some time in the near future.

mknod64(2)

To accompany the 64-bit dev_t, Andrew also merged a 64-bit version of mknod(2), the appropriately named mknod64(2). Until glibc is updated, the mknod(1) tool in coreutils will continue using the old mknod(2) and the old dev_t. To facilitate testing, I wrote a 64-bit version of the tool, mknod64. Source tarball, source RPM, and i386 RPM are available. With this tool and a patched kernel, 64-bit device numbers are your's to play with.

Red Hat 9

Brilliant. Good job, guys.

More gtk2 applications
Red Hat Rawhide has a gtk2-enabled gvim. Beautiful! I also finally moved to Evolution 1.3. I still cannot get spelling working, but hopefully soon. And it is beautiful. I still have a bunch of dependencies on gtk+ 1.2.0, but nothing of importance is actually using it. My entire desktop is now gtk2.

life

Trigger Happy TV makes me want to live again

procps

Finally merged the procps performance enhancements Red Hat (primarily alex) wrote:

• do not qsort the process list if we are not sorting
• read tgid from /proc/pid/status if it exists
• PROC_SKIPTHREADS flag for ps_readproc() to force only reading of (tgid != pid) to avoid lots of syscalls
• Look at flags in ps_readproc() to avoid reading /proc files files that are not needed.
• Support FILLMEM, FILLCMD, FILLENV, FILLWCHAN for above.

No new release yet with these goodies, but they are in CVS. CVS information and packages of today's CVS snapshot are available at: http://tech9.net/rml/procps/

O(1) scheduler

Turns out Linus's keen interactivity backboost hack is not all so keen -- it caused a severe starvation issue in some odd loads, primarily with setiathome. It was backed out in 2.5.67. Ah well.

Camera

The Canon 10D is turning out to be one of the best purchases I have made in some time. I truly enjoy it. Now if only I can find a reason to still use my beloved 35mm...

I applaud Zaitcev's 22-Mar-2003 journal and his 28-Mar-2003 update.

I forgot to mention in my last posting that procps 2.0.12 was released last Friday. Tarballs and RPM packages are available. Nothing too critical... a few cleanups and the removal of oldps(1). Oh, and a major bug fixed by axboe in vmstat(8) causing a fpe under 2.5.

The next release will hopefully have a whole slew of performance optimizations contributed by alex and Red Hat. Many of them are NTPL-related (the new threading package in glibc 2.3 and the 2.5 kernel - also back-ported to 2.4 for Red Hat's next release) but some are general enhancements, too. Looking very nice.

On Kernels: Misc. scheduler hacking and testing. The interactivity complaints in 2.5 are pretty much all squashed and everyone is happy. Except a potential regression/remaining issue in Andrew's latest 2.5-mm. We will see what that turns up. Some patches have surfaced on a full 32-bit dev_t. Better late than never. Maybe.

On Code Freezes: I promise to stop wishing for a code freeze out loud.

On Work: Working on some interesting projects (and fixing some not-so-interesting bugs). Pretty fun, although I long for 2.6.

On Cameras: I got my Canon EOS 10D today. Wow. Nice. There have been some complaints over sharpness and saturation vs. the Canon D60. I never owned a D60, so I cannot compare, but this thing looks amazing to me. I think I want to get a wider lens... my widest, at 28mm, is a fairly standard 44.8mm on the D10, with its cropping factor. I would really like the Canon 16-35mm f/2.8L but I think I will have to settle for the Canon 17-40mm f/4.0L when it comes out. One nice thing about the 1.6x crop (otherwise not my favorite feature) is that my favorite lens, the Canon EF 50mm f/1.4, is a nice 80mm.

On Evolution: Still playing with the Evolution 1.3 snapshots. They are really quite usable, but I still cannot get spell checking working. Without the spell check, I cannot switch from Evolution 1.2. The problem seems to be that my dictionary is not even detected. But it is installed; everything else detects it. Speaking of Evolution...

On books: Bought a couple books on Emerging Technology and Swarm Intelligence. Chaos/Complexity theory is a huge interest and fascination of mine. These similar topics will hopefully spark my interest in some new fields.