fyi1183's comments

fyi1183 | 7 years ago | on: Temporal side-channels and you: Understanding TLBleed

Maybe the answer is "wait and see the full details when they become available", but is there an example of code that is hardened against cache side channel attacks but would be vulnerable against TLB side channel attacks?

fyi1183 | 7 years ago | on: The advantages of an email-driven Git workflow

The main problem with HTML email is that it breaks interleaved responses ("bottom posting").

Bottom posting is so useful that even Outlook users reinvent it, badly of course, using different text colours etc.

It's been decades now, why have none of the advocates of HTML emails fixed this really basic problem?

fyi1183 | 7 years ago | on: The advantages of an email-driven Git workflow

Phabricator is decent in many ways, but it's terrible at handling patch series. Most people don't seem to be aware of the feature at all, and it's not integrated at all into tools like arcanist.

fyi1183 | 7 years ago | on: 500px will no longer allow photographers to license their photos under CC

I'm saying that it very well could have been intentional, yes. Not in the sense of somebody at Google targeting Blender specifically (that's possible but seems very unlikely), but in the sense of somebody at Google trying to see how far they can push forced monetisation through algorithmic coercion.

I don't think we have enough information to say for certain what really happened.

fyi1183 | 7 years ago | on: 500px will no longer allow photographers to license their photos under CC

> once the humans at youtube are alerted about the problem, the videos are put back up, as in the case of the blender videos. But if it was an intentional human takedown, the videos wouldn't be put back up.

It could also have been an intentional trial balloon, to test the waters to see how much they can get away with. Politicians do that kind of thing all the time.

fyi1183 | 7 years ago | on: Linux: Introduce restartable sequences system call

I suspect that something like a heap implementation could use this. For concurrency, you want different cores to use different pools to avoid atomics. In practice, this means per-thread pools are used today, but this rseq feature seems like it would allow using per-core pools instead. That would save memory and probably be even better for cache locality when a core is shared by multiple threads.

fyi1183 | 7 years ago | on: A Problem That Only Quantum Computers Will Ever Be Able to Solve

This is basically the TCS version of a clickbait headline. It's a separation of BQP and PH by an oracle. Certainly a nice result, but to put it into context, we also have a separation of P and NP by an oracle. Yet, we are very far away from actually proving that P and NP are distinct.

fyi1183 | 7 years ago | on: Ask HN: What comes after BitTorrent?

There's torrent via I2P, which provides a different anonymity-vs-performance tradeoff compared to normal BitTorrent.

I would say that BitTorrent just fits is particular design constraints fairly well, so I don't see anything replacing it without changing the use case patterns.

fyi1183 | 7 years ago | on: Intel demonstrates a 28-core processor running at 5GHz

Exactly. Keep in mind that AMD is currently selling 32-core chips.

They don't go up to that insane frequency, but still. There's plenty of opportunity to shop around if you want really beefy systems, which is a very refreshing state of affairs compared to just two years ago.

fyi1183 | 7 years ago | on: Intel Announces Optane DIMMs

I don't really know much about memory controllers, but being able to mask at the byte level seems like an important optimization. Without that, many writes will have to do a read first to them merge the read bytes with the dirty bytes.

fyi1183 | 7 years ago | on: Python’s For - Else

On the other hand, when you do run across this construct in the wild, it is trivial to look up what it does and learn. I imagine that's how most people learned about it, since it doesn't exist in other languages.

In a way I find your comment contradictory: on the one hand, you appreciate and embrace that the body of common knowledge can change. On the other hand, you use the current state of common knowledge as an argument against doing things that can improve the common knowledge.

fyi1183 | 7 years ago | on: Python’s For - Else

The if you're talking about ends in a break.

To me and many others, having an else associated to an if that ends in break/continue/return is a code smell, because it misleadingly suggests that there are two possible paths of control flow that reach the code after the if/else, when in reality you can only reach that point through the else block.

fyi1183 | 7 years ago | on: Python’s For - Else

Your suggested replacement duplicates the break condition, which is not ideal for maintainability.

Also, it only happens to work due to Python's variable scoping rules. I have wished for a for-else construct in C and C++ many times: having to broaden the scope of a loop iteration variable just to duplicate a loop break check really sucks.

fyi1183 | 7 years ago | on: Python’s For - Else

Funny, I actually like for-else because it can simplify loop exits.

First of all, the core of a linear search loop always has two exits: the break and the normal (unsuccessful) loop exit.

But in a lookup-or-insert pattern, a regular for loop has two possible states that the system can be in at the end of the loop. With a for-else loop, you can put the or-insert part into the else block, so that there is a simpler invariant: after the loop construct, the element always exists and has been found.

I was honestly surprised by all the negativity in this thread. To offer an alternative opinion, there have been plenty of times when I missed having for-else while writing C.

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