nikhil.io

Linux and Switching

The problem isn’t CPU power. The CPU on any modern PC is going to blow away the processing power of any sort of network switch you’d care to buy except the really high-end ones. (Really high end. So high end that unless you already know them by name you are not going to want to buy them)

Offloading to the GPU would make things worse, not better.

The problem is latency. It takes time for the PC to take the buffer from the NIC, copy it to the to the main memory, process it on the CPU, copy it back down into a buffer, and then push it out to the network. All this copying around takes time. You could have a 30000 GHZ processor and it’s not going to help you out any.

No amount of programming or GPU offloading is going to make your I/O faster or have less latency. This needs to be done in the hardware. PCs are not designed to handle this. They are designed to have huge cache’s were you take a huge amount of data and process it through loops. This is exactly the sort of thing you do NOT want on a switch.

With a switch you want small buffers. You want small buffers optimized to the speed of the networks they are connected to and have the ability to shuffle information from one port to another. You want to get the information in and out as quickly as possible.

That being said I have no doubt that a Linux switch based on commodity hardware would have no problem keeping up with a 1Gb/s or even 10Gb/s network and having performance similar to any typical corporate switch.

The problem then is one of cost, energy, and space. A network switch takes up almost no room on a rack. It uses little electricity and creates little heat compared to a PC-style corporate Linux server. It has lots and lots of ports.

To create a Linux commodity-based switch with 20 or 40 ports the thing is going to be huge, expensive, and hot.

So yes while it can be done it’s not practical.

On using a Linux box as a switch.

Child Endangerment

A mother in suburban Chicago breathes a huge sigh of relief this week, as she was reunited with her 8-year-old son Kevin, who was accidentally left at home alone as the family went on vacation to Paris. Apparently no one had noticed the boy was missing on their drive to the airport and through airport security and while boarding the plane.

Only once when they were in flight did the mother sense that a cherished family member may not have been present. She then shrieked, Kevin. She would rush home where she, along with police, found the boy unharmed physically, though he may deal with abandonment issues for years to come.

In addition to the boy, the police also found two career criminals who appeared to have suffered great bodily damage while attempting to rob the house. One man had been shot in the groin with a BB gun and had his hands severely burned by a hot doorknob. The other man had a nail and pieces of glass Christmas ornaments lodged in his foot. Both men also miraculously survived being hit in the head with a paint can that was apparently swung from a rope at high speeds, something which would normally crush a human skull.

Child Protective Services say they will not remove the child from the family since they believe it to be only a one-time occurrence, and certainly not something that could happen again the next year.

– Hari Kondabolu on Wait Wait… Don’t Tell Me!

Telling People Things

What’s going on is that without some kind of direct experience to use as a touchstone, people don’t have the context that gives them a place in their minds to put the things you are telling them. The things you say often don’t stick, and the few things that do stick are often distorted. Also, most people aren’t very good at visualizing hypotheticals, at imagining what something they haven’t experienced might be like, or even what something they have experienced might be like if it were somewhat different.

and

When people ask me about my life’s ambitions, I often joke that my goal is to become independently wealthy so that I can afford to get some work done. Mainly that’s about being able to do things without having to explain them first, so that the finished product can be the explanation. I think this will be a major labor saving improvement.

Chip Morningstar, “You can’t tell people anything”

Eggos!

From a Bloomberg article on frozen food:

After a four-year slump, Kellogg Co., maker of Special K and Frosted Flakes, has returned to growth in recent quarters. That’s thanks in part to a boost from Eggos, which benefited from its prominence in the hit Netflix series “Stranger Things” as the favorite food of a mysterious telekinetic girl named Eleven. The brand’s sales are up double digits in each of the last two quarters.

Eleven smiling

Oliver Burkeman on Hasty, Short-Term Thinking

It is alarming to consider how many major life decisions we take primarily in order to minimise present-moment emotional discomfort. Try the following potentially mortifying exercise in self-examination. Consider any significant decision you’ve ever taken that you subsequently came to regret: a relationship you entered despite being dimly aware that it wasn’t for you, or a job you accepted even though, looking back, it’s clear that it was mismatched to your interests or abilities. If it felt like a difficult decision at the time, then it’s likely that, prior to taking it, you felt the gut-knotting ache of uncertainty; afterwards, having made a decision, did those feelings subside? If so, this points to the troubling possibility that your primary motivation in taking the decision wasn’t any rational consideration of its rightness for you, but simply the urgent need to get rid of your feelings of uncertainty.

Oliver Burkeman, “The Antidote”

Freeman Dyson on Richard Feynman

When we arrived we were introduced to Henry Bethe, who is now five years old, but he was not at all impressed. The only thing he would say was “I want Dick. You told me Dick was coming,” and finally he had to be sent off to bed, since Dick (alias Feynman) did not materialise. About half an hour later, Feynman burst into the room, just had time to say “so sorry I’m late. Had a brilliant idea just as I was coming over,” and then dashed upstairs to console Henry. Conversation then ceased while the company listened to the joyful sounds above, sometimes taking the form of a duet and sometimes of a one-man percussion band.

and

In the evening I mentioned that there were just two problems for which the finiteness of the theory remained to be established; both problems are well-known and feared by physicists, since many long and difficult papers running to fifty pages and more have been written about them, trying unsuccessfully to make the older theories give sensible answers to them. When I mentioned this fact, Feynman said, “We’ll see about this,” and proceeded to sit down and in two hours, before our eyes, obtain finite and sensible answers to both problems. It was the most amazing piece of lightning calculation I have ever witnessed, and the results prove, apart from some unforeseen complication, the consistency of the whole theory.

Freeman Dyson, “Maker of Patterns” (via Nautilus)
Inside Men

Inside Men (2015)

IMDb

Rating: B+

Longer than it should’ve been and unevenly paced. Predictable ending. Still very enjoyable, since I’m a sucker for a good vengeance flick. Lee Byung-hun was absolutely fantastic (first saw him in “I Saw The Devil”.) Found myself hating this guy’s character with the same bile as Imelda Staunton’s Dolores Umbridge.