Muli Ben-Yehuda's journal

July 25, 2003

Paul Mackerras, Low Level Optimizations in the PowerPC Kernel

Filed under: Uncategorized — Muli Ben-Yehuda @ 11:26 PM

Wed, 15:00

After Jon Corbet’s porting to 2.6 talk, went to hear Hirokazu Takawa talking about porting Linux to the M32R architecture. This talk, how shall I put it gently, left a lot to be desired. The speaker, while obviously knowing what he was talking about, spoke in a monotone, broken english, that made following along practically impossible. I gave up and decided to read the paper instead, and went out in the middle.

After this talk, went to eat lunch with zwane, sarnold, Nick Piggins and Orna. For some inexplicable reason, we ended up in the mall’s fast food court, and the food’d quality was about as good as could be expected – that is, not at all.

After lunch, went to hear Matthew Porter’s Bringing PowerPC Book E Processor to Linux talk. This was a pretty good talk, which was a relief after the previous two talks. Low level, dealing with memory management and the peculiarities of the Book E processor, which is a PowerPC variant.

The I went to hear Paul Mackerras, on Low Level Optimizations in the PowerPC Kernel. This was an excellent talk, dealing with three low level optimizations: PTE management, memcpy implementations and cache management (the PPC architecture is not cache coherent). I really enjoyed this talk, not in the list because Paul Mackerras is a great speaker, clear and interesting. I wonder if I could get a PPC machine from work to play with 馃槈

At this point, I have to make a small disgression. OLS thus far is not what I expected. It seems that I don’t have anything to talk to people about, with syscalltrack development in a stand still, and my kernel work being too trivial to mention, in my (probably wrong) opinion. It’s probably all in my head, but it makes me feel pretty lousy. after Paul’s talk I headed back to the room since my eyes were burning from the contact lenses I left in over night (don’t do that, kids). I ate a quicky dinner, and instead of going back, fell asleep and woke up at 1 AM. Missed the last talk of the day and the welcome reception. Oh well. I briefly considered going out to a random pub and finding who was there, and instead read until sometime in the early morning, and then went back to sleep. So much for OLS, day 1.

Next: Dave Jones on resurrecting unmaintained code.

Jon Corbet’s Porting Drivers to 2.6 talk

Filed under: Uncategorized — Muli Ben-Yehuda @ 11:26 PM

Wed, July 23rd, 10:00 AM

Jon Corbet on Porting Drivers to 2.6

I missed the first few minutes of this talk due to writing down the previous day’s escapades. Tuning back in, Jon is talking about the changed interrupt handler signature. Nothing new so far, I’ve been following this stuff pretty closely during 2.5 development.

Next slides: the linux device model. Impact on drivers can be small, since things are mostly handled at the bus level. Again, nothing new.

Just spotted Ted T’So sneaking into the talk.

Considering heading out of the talk to go and reply to my email… should I? No. But I know this stuff! Yes, but you’re here to listen to talks, not to do email!

Obviously, the email daemon won and I ended up going out of the talk. In my defense, I really did know what he was talking about – even wrote code to interface with some of it. Took care of email, met Bill Irwin and Dave McCracken. Continued debugging my initscripts problem. The problem was that /etc/init.d/network would claim that the network was up, even when it wasn’t. Looking at the logs, they were filled with garbage such as “Jul 24 00:31:22 hydra ifdown: ./ifdown: ++: command not found”. Eventually, I found the problem – /etc/init.d/network calls /etc/sysconfig/network-scripts/ifdown, which executes a function from another file, which sources /etc/sysconfig/network-scripts/eth0. Somehow, this file was filled with garbage. I removed it, and now everything is working fine. Hmpf.

During the break, met Shawn Starr, Andrew J. Hutton and erikm.

Next: Paul Mackerels, Low Level Optimizations in the Power PC kernel.

What we did on Tuesday

Filed under: Uncategorized — Muli Ben-Yehuda @ 5:48 PM

Wed, July 23rd, 10:00

On Tuesday morning, we woke up pretty early, at 6 AM in fact. I blame the jet lag. We went out in search of breakfast, strolled through byward market, which was in the process of being set up, and eventually ended up at Tim Horton’s, in Rideau Mall. So much for our search for quality food. At 8 AM, we went to the local super market, Loeb’s and bought 91CAD worth of food. Took the food to the room, arranged it in the fridge and cardboards, and went back to sleep.

Around 2 PM, we woke up. Cooked a tasty lunch from the food we bought, and then went to register for OLS (happy happy joy joy!). At the registration desk, we discovered that no wireless cards will be supplied this year. Since the thought of having no network access was appalling (for me, at least… Orna could handle it just fine) we set out to buy a wireless card.

The first step was to take down the model numbers of all of the cards available in the local computer shop, compucenter. Then, I went to chapters’ internet cafe to see which of the cards is supported in Linux. Buying a non supported card can be fun, if documents are available, but I needed it working now. Turns out that only one(!) of the cards, a USR 2410 card, works. While I was googling, Orna was shopping at chapters. I told her that I’m done, looked at the gazillion books she picked up, waited for her to pay for them, and then we went together to buy the card – only to find someone else from OLS bought it! The only copy! Argh!

We immediately set out on a long walk to the next nearest computer store in the area, and bought a card that appeared to be supported, a D-Link DWL-650+ card. The card looked like it requires a driver from, which requires net access to download. Chicken and egg problem, indeed. What I intended to do was boot into the never used windows partition on hydra, my IBM laptop, use the drivers supplied with the card to download the linux driver, and then use that. Calm in the knowledge that I have a card that should work, while still experienced enough to have that ominous feeling in the pit of my stomach that says anything that can go wrong, will, we went back to the hotel room. In the room, I discovered that I have no CDROM drive on the laptop, and thus no way to download the Linux drivers. Banged head against wall several times.

By this time, Orna was growing restless (to put it mildly) that we’re chasing after wireless cards instead of touring Ottawa, like good little tourists (it’s my diary, I’m allowed to whine). So we went out to look at the river and talk about various things, try to synchronize our expectations. Eventually we went back to Les Suites, after buying disinfectant for my hand and Taco Bell for dinner. At the lobby, we met the illustrious zwane and the magnificent sarnold. The four of us went out to the to the Highlander Pub, where much merriment was had. Eventually stumbled back to the hotel (I had a Vodka Martini and some Cognac, *hic*), and went to sleep.

In the morning, I woke up early and went to OLS’s network area to download a driver for the wireless card. After banging head against wall, a kernel compile and some heavy RTFM’ing, discovered that contrary to what I thought, the card is not really supported!. Orna took charge, and we went back to the store and returned it. By the time we got back to the congress center, it was 10 AM, and Orna went to hear the performance talk, while I went to Jon Corbet’s Porting Drivers to 2.6 talk. On the way in, met the venerable Behdad Esfahbod.

Next: Jon Corbet’s Porting Drivers to 2.6 talk.

up and awake at 6 AM

Filed under: Uncategorized — Muli Ben-Yehuda @ 4:51 PM

Tue, July 22nd, 06:15

It’s six AM and I’m up and bouncy. I blame the jet lag.

Last evening, we walked around downtown Ottawa. We had good weather, and Ottawa is beautiful. Wide streets, very little traffic compared to what I expected, and people of many ethnicities. A few minutes of walking around were enough for me to ask Orna if she might want to live here :->

We stopped at chapters in order to check out the internet cafe and email Oleg about the wireless cards used at IBM HRL. Naturally, the internet cafe was out of order. Then we took the Ottawa Haunted Walk tour. Orna says it’s about typical, but I was disappointed with it. We didn’t get into any supposedly haunted locations, just stood outside and heard stories about them, which were mostly repetitive and didn’t have any “interesting” details. Orna says it was light on history, too. It was a nice excuse to walk through downtown for a couple of hours, though.

After the haunted walk ended at 21:30, we watched a light and sound show on parliament hill. Then we went looking for food at the Rideau Mall, and due to the late hour all we found was orange juice and Reese’s peanut butter cups. At least it was a good excuse to get the peanut butter cups 馃槈 Went back to the hotel room, debated which movie to watch on the hotel pay-per-view system – Orna wanted Holes, I considered Tears of the Sun. We ended up watching The Simpsons on one of the local TV channels, and eventually fell asleep.

OLS registration begins today!

Les Suites hotel

Filed under: Uncategorized — Muli Ben-Yehuda @ 4:42 PM

Mon, July 22nd, 17:57

The rooms in Les Suites are actually apartments. A fully stocked kitchen, living room, bedroom, rest room and a utility room, with washing machine and drier. Living in style, indeed…

When we got to the hotel, the person at the front desk gave us a room on the third floor. Upon opening the door, we reeled back from the stench of cigarette smoke. Once we stepped inside, we were deafened by the noise from the street. Orna immediately put on her assertive hat, went back to the front desk, and got us a non smoking room on the 17th floor instead. Yay!

While the new room was pretty good, it didn’t have any broadband available. We asked, but all of the broadband rooms were either taken or reserved, and we settled into our room. We learned that there’s free wireless coverage in the hotel, and I decided to buy a wireless card, unless one will be provided at OLS, like in previous years.

We slept for a few hours in the afternoon after checking in, for which Orna blames me. I blame the jet lag.

In preparation for OLS, I compiled and installed kernel 2.6.0-test1 on hydra. Can’t go to a kernel convention without running the latest kernel. Went smoothly, except for the new module init tools I had no way to download. Since I build mostly monolithic kernels, no big deal… I’ll download them when I get on the network.

Next: how we spent the first evening in Ottawa.

laptop futzing

Filed under: Uncategorized — Muli Ben-Yehuda @ 12:25 AM

This is the first in a series of notes I took / am taking during OLS.

Mon, July 22nd, 07:00 AM

Sitting in Toronto’s pearson airport and waiting for the flight to Ottawa. I took out the laptop to do something productive, although I can’t remember what it was anymore, and instead spent an hour chasing the init scripts to set a low timeout on dhcp, debugging a weird apm problem and figuring out the internal IBM client modifications to a custom RH7.3. There’s a lovely expression for this sort of thing, coined at MIT (where else?) but I can’t remember what it is now. Shaving yaks, perhaps. Will check when I get back online. [checked, it’s Yak Shaving].

The flight from Israel was rather uneventful, and thankfully we spent most of it asleep. Due to booking the flight pretty late, Orna and I had separate seats, both window seats on aisle 14. Once we boarded the plane, we asked a nice UN soldier to switch with one of us, and he did. The in flight entertainment was one of the X-men movies, the god awful “About Schmidt” with Jack Nicholson and something else we missed since we slept. When we went to see “About Schmidt” in the cinema, we walked out of it in the middle, it was so bad. This time Orna seemed to enjoy it, and I couldn’t walk out of a plane cruising at 39,000 feet.

Next, The Les Suites hotel.

Blog at