Quoting: 3zekieleventfd is actually efficient enough for its purpose I would expect. But the issue is, the inner counter is - by spec - maintained by the kernel. So it means many round trips between kernel and user space ... Which will limit perf, and I guess that is why you can not just poll it as much as you want. And that is the syscall spec, can't do much about it.
Futexes on the other hand were made so that you only go to kernel space if you can not take the lock ownership/if the semaphore is at 0 (basically a yield). So you have much less round trips with futexes. They are also stored as a simple `intptr` (an address) whereas eventfd looks like that:
struct eventfd_ctx {
struct kref kref;
wait_queue_head_t wqh;
/*
 * Every time that a write(2) is performed on an eventfd, the
 * value of the __u64 being written is added to "count" and a
 * wakeup is performed on "wqh". A read(2) will return the "count"
 * value to userspace, and will reset "count" to zero. The kernel
 * side eventfd_signal() also, adds to the "count" counter and
 * issue a wakeup.
 */
__u64 count;
unsigned int flags;
int id;
};
From the look of it, eventfd will be more real time (you will wake up as soon as something happens if you have the priority), whereas futex side, you will wake up at your next quantum clearly (I only see mechanism unsuspending you, nothing scheduling you). Futexes also do not hold a list of who is waiting, they are just a counter. So the first one who comes and retake the lock wins seems. It's coherent since the scheduler is fair anyway.
So I would say, they just fill purposes that are orthogonal. I would typically use eventfd for IO related waits, or if I need something a bit more real time. And futexes for all the rest.

Ack. I don't know eventfds well enough to actually have a proposal to improve it. But agreed, having futexes go through the kernel unconditionally is completely in contradiction with them being futexes, so a new syscall is reasonable.

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Quoting: 3zekielShort answer: they kinda already tried that at first, and judged it to be a dead end.

Fair enough.

Quoting: 3zekielLong answer:
Modifying an existing (set of) syscall(s) is extremely limited. You can not break compatibility in any way, since that would break thousands of apps, with no way for users to fix it. Contrary to libraries, you can not just install another kernel, or use a lightweight container to fix a kernel ABI breakage. So all issues with that syscall set are pretty much set in stone.

Sure, but that doesn't mean you cannot provide the same functionality more efficiently. The point was eventfd doesn't scale, and making that scale doesn't necessarily have to interfere with its functionality.

Quoting: 3zekielMore generally, it seems more natural and clean to use a tool that is actually made to fix your issue. File descriptors (which eventfd is based on) are made to deal with file-like stuff (that's a lot of stuff in Linux). Futexes are made to deal with synchronization issues. Futexes are also made to be used in large numbers, file descriptors... not that much (the overhead in memory and so on).

Everything is a file. In fact the few things that Unix didn't make a file turned out to be the most problematic areas (pids and signals notably). At least the pid problem is remedied with fds (pidfd), and if signals aren't already, I'm sure they will be turned into fds too.

I said all that to say that given how central fds are, it's worthwhile to make sure eventfd is actually efficient, rather than keep trying to work around it.

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Quoting: jordicomaWhat? A functionality coming from windows world that its good?

It's not necessarily good. If windows has feature X, games will depend on it. Now it may have been better if games did Y instead, but that doesn't exist and they are stuck with X.

Just because Linux now needs a way to implement X doesn't mean that X was the best option, just that because of windows we are now stuck with it.

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I wonder why they didn't instead try and make eventfd more efficient?

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Quoting: GuestWhy make parts readily available if you’re telling us it’s a bad idea to replace them?

To be fair, they did mention a few times in the video to "leave it to the professionals", which sounds like they do think it's ok to repair / change parts, just not by any rando with a screw driver.

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Quoting: elmapul

Quoting: ShabbyX

Quoting: BielFPs

Quoting: ShabbyX

Quoting: BielFPs... that Phasmophobia requires Cortana to use the voice functions of the game, ...

Wow, that's so braindead.

They did this to take advantage of the Cortana's AI, despite the "Windows dependency" part, I think this was actually pretty smart of them.

That's a sure way of making sure your game is completely unplayable in 5 years is what that is.

at the worst case scenario, they disable this feature and the game do work.
you seem like someone who prefer an game to never exist than to exit for a few time.

Disclaimer, I know nothing about this game, if the feature is entirely optional, then sure, that's fine.

If it's a core part of the game, then making it depend on some tech existing and shipping by the operating system is braindead. API's change, technologies change, it's not like the Cortana API has been standardized. In a few years Cortana will change enough that the game would be borked.

Adding voice recognition to games is a smart idea, sure. Just the technology used to implement it was wrong. They could have used some third party library (open source preferable of course) they could ship and not worry about it changing.

Again, if the feature can be disabled and is entirely optional, then sure, go nuts.

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Quoting: BielFPs

Quoting: ShabbyX

Quoting: BielFPs... that Phasmophobia requires Cortana to use the voice functions of the game, ...

Wow, that's so braindead.

They did this to take advantage of the Cortana's AI, despite the "Windows dependency" part, I think this was actually pretty smart of them.

That's a sure way of making sure your game is completely unplayable in 5 years is what that is.

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Quoting: BielFPs... that Phasmophobia requires Cortana to use the voice functions of the game, ...

Wow, that's so braindead.

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Quoting: denyasisSo honest question....
Is CK3 so much better than 2 that is worth buying 3? Or should I hold off until it gets fleshed out with a couple more expansions?

I have CK2 and most of it's expansions, which cost a lot. I haven't played it much and would basically be a new player.... I guess I'm worried that I would spend a lot of money on a game I fundamentally already have.

I may be stating the obvious here, but you should probably first play the game you already have, see if you even like it, before you decide to by the sequel :D

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> One of the stats they gave out showed that Cannibalism has been adopted 14,000 times! Oh my.

Well it's just a game. Like we keep playing games where we kill people and animals left and right, it's not like we have any desire to do that in real life.

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