Category Archives: Edumacation

Welcome to Los Alamos National Laboratory

Today I officially accepted Los Alamos’s offer for a position as a technical staff member in CCS-1. In reality, there are only a few changes as a result of changing from a graduate student to technical staff:

  • I get paid more (Woo!)
  • I get vacation and sick days (Woo!)
  • I can take my LANL-owned laptop home without writing a safety plan for my apartment.

And before anyone asks, YES, I STILL INTEND TO GRADUATE AS SOON AS POSSIBLE! It looks like my duties over the next year will include:

  • Writing a health monitoring subsystem for ORTE on non-BProc systems
  • Modifying the BTL interface to better support RDMA communication (For a bunch of stuff, including my thesis)
  • Working with various groups at LANL trying to generate performance data on Open MPI
  • Planning LANL’s Open MPI presentations at SC’06
  • Open MPI support (ugh!)

So same old thing, slightly different title.

hehe.. Fooled them all…

My oral qualifier exam was on Friday morning. I passed, so by definition it went well. As soon as I get a couple more signatures, I will be “PhD Candidate Barrett” to you. Now all I need to do is find something that might look something like a thesis topic. Maybe something will just *poof* into my brain… right… Anyway, nothing interesting to report on the exam front. Amr had some interesting comments I need to think about.

That’s a strange place for a horn…

Why do I always end up playing with linkers?

This week is apparently the attack of the satanic linkers week. In both LAM 7.1 and the ISI logger project, I’m fighting with linkers to make them bend to my will. Which is probably my first mistake – I should just give up and let them bend me to their will. But I’m stubborn and believe that I’m smarter than your average piece of code, so on we fight.

On the LAM front, I’m trying to figure out why I can’t seem to intercept calls to deallocate_pages in the OS X libc memory management code. deallocate_pages is a call that should happen right before the call to vm_deallocatepages, which is the OS X equiv to sbrk() with a negative number for the second argument. Why do we need to do this, you might ask? Well, using networks like IB or Myrinet requires pinning pages in memory so that they are not moved around while a DMA transfer is going on. Pinning pages is really expensive, so you don’t unpin unless you really need to. So the bottom line is that you need to know when memory has been free()ed by the system, so that you don’t return memory to the system while it is still pinned. On most Unix systems, you just use ptmalloc and intercept all the calls to malloc(), free(), and friends. On OSX , it is a bit more complicated, since there is this crazy two-level namespace thing going on. So instead, we try to hook into the lowest level of things. Still not sure if this is going to work – need to spend some more time on the issue….

On the Logger front, it’s much simpler. We seem to be encoding the wrong path in an rpath somewhere, so we aren’t finding shared libraries at runtime in certain circumstances. Obviously, this isn’t a good thing, but is probably just a shell scripting error or something similar, rather than a major misunderstanding as to how the platform’s linker actually works. So all is probably going to be ok on this front in the next couple of days. At least, I hope so.

San Fran is a weird place

Went up to the bay area this weekend for the Bay to Breakers 12K race. Very entertaining race. For starters, there was a definite lack of port-a-potties in the starting area, yet there were many along the way. Follow that up with a group of guys who carried a fully operational bar (including the bartender and multiple kegs) the entire 12K and you kind of get the picture. Wandered around San Fran on Saturday with Rachel, which was entertaining – we only got lost 3 or 4 times… Which isn’t too bad, all things considered. Drove back Monday, which was more eventful than usual. A rock decided to cause significant damage to my windshield, so that kinda sucks.

Stupid Computers

Something evil has happened today such that I don’t seem to have an account on many of the OSL machines any more. This is probably going to take an afternoon to get worked out… Blah.

Fire bad. Tree pretty.

Not how this was supposed to work at all

It’s official. I’m starting grad school again in early July back in B’ton. God, I hate when that happens.

Running

Statred running again. Got in desperately bad shape. Getting better. Stupid San Diego weeks, ruining routines.

Congrats!

Jeff finally defended. He kicked butt in the talk. And Indiana’s stupid timezones struck again.

English? We don’t need no stinkin’ English

I appologize for the lack of, well, decent writing in today’s entry. I just don’t feel like putting forth the effort to conform to the standards set forth by…. ummmm…. civilization, I suppose. Cope.

Why do I want to go back to Indiana again?

It’s currently 74 degrees outside, with lots and lots of sun. I’m working from my apartment, from which I can see the channel to the marina. And Buffet is playing. If I had a margarita (and wasn’t trying to figure out how the RTI-s packetization works) life would be perfect.

Oh, I’m sorry. Did I break your concentration?

Computer People Suck

I’ve been filling out applications to a couple of grad schools this week. All four schools have some form of online application. And all four online applications suck. USC has two different online applications, both of which are impossible to follow. Cal’s is actually reasonable, except for the fact that it asks the same question multiple times and doesn’t automatically load the question set that matches your department – there are some instructions, but they are in about 4 different places. And Stanfords is, well, painful. You would think that people would be able to write decent software.

Computer People Really Suck

Someone actually managed to get OS X to return two lines from running the “hostname” command. I’m really not sure that is possible, and it really annoys me. I’m trying to figure out how this is possible, but it is breaking LAM’s configure script. I really don’t want to fix what is clearly not allowed (you can’t have multiple hostnames – it just isn’t right). Anyway, it looks like we will be releasing LAM 7.0.3 sometime in the next week. It wouldn’t be a Super Computing conference without a LAM release. No huge new features, just some bug fixes.

Poker Night

After watching Notre Dame finally win a game (woo hoo), went up to Santa Barbara to play poker with the ND crew. Dave came up with some crazy ass games – not all that surprising I suppose. I had about one good hand the entire night, but managed to hold on to end up a bit on the night. I was happy to find some entertainment for the night.

Advice to live by

Advice to live by:

Rome did not create a great empire by having meetings, they did it by killing all those who opposed them.

Exact source unknown, but been flying around the internet….

Machines and Myrinet cards are dying all over the place. Yeah for sysadmin duties…