Archive for May, 2007

Solaris TCP Latency for HPC

May 31, 2007

Because the Solaris TCP stack’s default settings are optimized more for bandwidth than latency, Solaris HPC users and others with latency requirements may find the following note useful.

Using default TCP and driver settings on Solaris 10, MPI zero-length ping-pong latencies are measured to be about 60us on Solaris versus 25-30us on Linux. The issue is a result of Solaris being tuned by default for bulk transfers and reduced processor utilization through the use of interrupt blanking or interrupt coalescing. Turning off blanking reduces the Solaris latencies to be on par with those of Linux. It also increases processor utilization and will reduce performance on large message transfers, so there is a tradeoff to be aware of.

To turn off blanking on a bge interface, add the following lines to /etc/system:

set bge:bge_rx_count_norm=1
set bge:bge_rx_ticks_norm=1
set dld:dld_opt = 2

To turn off blanking on an e1000g interface, use a combination of ndd tunables and entries in the e1000g.conf file. This support is currently available under Open Solaris and will be available for Solaris 10 in a future update release. The config file entries are:


The ndd commands (which are not strictly related to blanking, but may improve application performance in some instances) are:

ndd -set /dev/e1000g0 tx_interrupt_enable 0
ndd -set /dev/e1000g0 rx_bcopy_threshold 128

Sun’s new dual-ported mulithreaded 10 GbE interface card, can be tuned by adding the following lines to the nxge.conf file:



El Capitan by Moonlight

May 6, 2007

[el capitan, yosemite, by moonlight]

Which Superhero is SUN?

May 5, 2007

Back in January, I took the Superhero Personality Quiz. Today, I took the same quiz on behalf of Sun, wondering which superhero would best match Sun’s corporate personality. Just giving you the answer wouldn’t be any fun so I kept notes on how I answered each question. Obviously, this is one engineer’s personal view of Sun. You might try this yourself and see which superhero you think Sun most resembles.

Here are the questions and my answers.

Do you like to fly? Doesn’t every public company? You bet!
Do you like to wear a cape? We’re engineers, not flashy dressers.
Are you very virtuous? We try to do the right thing. As an employee, I’m proud of that.
Are you a persistent do-gooder? No more or less than most other for-profit companies.
Are you somewhat reserved and easy going? We like to kick butt and have fun.
Are you an intelligent geek? Say it loud and say it proud!
Do you like redheads? Sun is an equal opportunity employer.
Are you accident prone? We’ve had our share of missteps over the last six years or so.
Are you a hopeless romantic? Hardly. Pining for those $60 stock prices doesn’t count, does it?
Do you have a good sense of humor? We bought Hewlett & Packard last year, right?
Do you like hi-tech gadgets? We like hi-tech, high-value gadgets.
Did you have a bad childhood? Not so much. We were a bit of a bad boy, but we’re maturing.
Do you have a dark personality? With a name like SUN? Darkest we’ve been recently was Project Blackbox.
Do you wear thongs? A bit personal, but no. Have been known to sport electrostatic bracelets on occasion.
Do you have long hair? Some of us have an affection for pony tails.
Are you VERY comfortable with your body? Not so much. We have a history of rearranging our parts on a fairly regular basis.
Do you value independence and privacy? We like doing our own thing.
Do you ever wear a pushup bra? What you see is pretty much what you get with us.
Are you beautiful? We are a lot more the geek than the supermodel.
Are you good at reading people? We lost our way for awhile, but recent revenues indicate we are doing better.
Do you like to be in the limelight? No geek truly enjoys the limelight.
Are you young at heart? 25 years old and still an adolescent.
Are you good at acrobatics? Not bad. Our best event is chasm crossing.
Are you a little naive? At this point, we’ve been around the block several times.
Are you easily angered? HOW DARE YOU! (uh, not so much)
Do you have hidden strength? Sign an NDA and take a look our upcoming product launches.
Are you a loner? We are very open and community oriented with a strong set of partners.
Do you often hurt people without realizing it? We would like to think we don’t.
Do you move a lot? Home has been California since we were a wee corporation.
Are you athletic? Not in a flashy way, but we do have staying power.
Are you a fast runner? We are more of a long-distance runner.
Are you a flirt? We tend to say what we mean and deliver on what we promise.
Are you extremely talented in only one area? Well, yes, but don’t say it like it’s a bad thing. Our area is pretty big.
Will you sometimes go too far to get your way? Not with our standards of business practices.
Are you interested in space travel? Java is on Mars right now.
Do you have strong willpower? You bet.
Do you have one object that you highly value? That used to be our stock price. Hoping it is again soon.
Have you ever stolen anything? No. That was easy.
Do you get in many physical fights with girls? Actually, NO physical fights with girls.
Do you like animals? You probably know the Network is a Computer. But did you know Network was a dog?
Do you use people to get your way? That’s a big corporate philosophy question, isn’t it?
Do you like bad boys(or girls)? You mean people who might think differently, try new things, experiment with new technologies? Bring ’em on.
Are you much of a drinker? Mostly coffee, tea, and hot chocolate.
Are you obviously powerful? See the product portfolio and our bank balance.
Are you a show off? Only insofar as is needed to compensate for our tiny Marketing budget.
Do you like to build things? THAT is our passion.
Have you achieved a lot from hard work? We think so.

Sun’s results:
You are Iron Man

Iron Man
Green Lantern
The Flash
Wonder Woman
Inventor. Businessman. Genius.
Click here to take the “Which Superhero are you?” quiz…

Library 2.0

May 4, 2007

I know a few people who use Delicious Library to catalogue their books, music, and movies. Mostly to keep track of what they have and what they’ve lent out. It’s a slickly done application with a nice look and feel and several input methods, including support for barcode scanners and using a Mac’s iSight to capture barcodes. I was tempted to try DL, but decided instead to try Library Thing.

Library Thing Logo

Library Thing works with books only. It lacks much of the polish of Delicious Library. It does work with barcode scanners like the <a href=":CueCat. It’s real saving grace is that it is web-based. By storing libraries in the network, Library Thing creates a community of book lovers. And with access to the libraries of 190,000 members containing almost two million unique works, Library Thing can suggest books you might like based on similar holdings in similar libraries, or suggest books that are tagged similarly to books you own. It’s also fun to see I have some unique books — books that none of the other 190,000 members have in their libraries. Likewise, it’s a kick to find members who share my interests and own some of the odder books I have in my library.

Take a short tour of Library Thing to learn more. You Delicious Library users (and others) can import your libraries into Library Thing if you’d like to experience the community aspects of the site.

I bought a :CueCat for $15 from Library Thing and have started scanning. As of this writing, I have scanned only 235 books, but if you like, you can see what I’ve loaded so far.

Mac Book Pro, Part the Seventh

May 3, 2007

I stopped at the Palo Alto Apple store yesterday to see if my battery was eligible for replacement under Apple’s latest replacement program. With a cycle count of about 180 and a current battery life of about 2.5 hours even after applying the latest battery software update, I thought it was worth a try. And it was, eventually.

The genius/tech at the Palo Alto store first said I wasn’t eligible based on my machine’s serial number and that of the battery. He determined this by removing the battery from my sleeping machine (which kernel panic’ed later as a result, but now seems okay.) After I told him I had come to the store based on this article, which didn’t seem to have any relation to serial numbers, he gave me a new battery.

As we were finishing, he mentioned that my machine was out of warranty. Which wasn’t true, since I had bought Apple Care coverage when I purchased the laptop. This was the second time Apple has lost track of this coverage. I called 1-800-APL-CARE and they fixed the problem, though it did take more than 15 minutes on the phone.

For those keeping track, here are the issues I’ve had so far with my Mac Book Pro. Click on a summary to read the full blog entry.

problem resolution
laptop arrives with dead superdrive laptop replaced
laptop wakes from sleep when moved top case assembly replaced
battery recalled battery replaced
fast ticking noise fan replaced
multiple black blobs on screen screen replaced
loud whistling noise power management system reset
poor battery performance (current blog entry) battery replaced

Logical Domains for UltraSPARC: Now available!

May 3, 2007

ldoms architecture diagram

Our group (SPARC Platform Software) has just released V1.0 of Logical Domains (LDoms) for the UltraSPARC T1 processor. With LDoms virtualization, you can run 32 separate Solaris instances on a single UltraSPARC-T1 based system. Customers with Sun Fire T1000 and T2000 systems or with Netra T2000 or CP3060 systems will find the downloadable bits here.

My colleague, Ashley Saulsbury, has more details about LDoms and virtualization on his blog. Or check out the official product page.

Did I mention LDoms software is free? Yes, I guess I did. 🙂