4 ms·

It absolutely can make a difference because if you have locks that are supposed to sync or wake up other processes you care about latency not cpu usage.

Dylan16807 5mo ago
What specifically are you saying can make a difference? I'm saying that extra overhead from making your lock work across processes should be very tiny. That overhead shouldn't add much more than a microsecond in either latency or CPU usage, compared to an in-process lock.
- CyberDildonics 5mo ago
  You were saying "reasonable overhead" makes no difference because something "isn't called much". This is not only ambiguous but also not true because latency is important. What calls specifically are you talking about between windows and linux? This was started by someone talking about WaitForMultipleObjects.
  - Dylan16807 5mo ago
    I wasn't excusing all overhead, I was excusing the difference in overhead caused by making the lock more flexible. Because that's what the discussion is about, a lock that can be shared between processes versus a lock that can't be. The penalty for being "too flexible". But assuming reasonable implementations, the difference between those two lock styles shouldn't be more than about a microsecond, should it? So that's fine for a lock that's only used 100 times a second. I'm not comparing windows and linux anywhere.
    - CyberDildonics 5mo ago
      I was excusing the difference in overhead caused by making the lock more flexible What are the two functions you're comparing and what is the actual difference in overhead that you're talking about? a lock that can be shared between processes versus a lock that can't be. This is a dramatic black and white difference, these would be used for two different things. In that case it's apple and oranges, one would be for interprocess communication and one wouldn't. the difference between those two lock styles shouldn't be more than about a microsecond, What are you basing this on? Do you have an examples or benchmarks of the actual calls and their timings? fine for a lock that's only used 100 times a second. Again, latency isn't about how many times something is called per second. That would matter for throughput.
      - Dylan16807 5mo ago
        > What are the two functions you're comparing Go ask this comment, because I'm continuing their comparison: https://news.ycombinator.com/item?id=48125795 https://news.ycombinator.com/item?id=48125795 > In that case it's apple and oranges, one would be for interprocess communication and one wouldn't. The whole point of the complaint was wtallis claiming the inter-process-capable lock was being used for locks that don't need it! That's the foundation of this conversation! > What are you basing this on? Basic coding knowledge and an assumption of competency. There's no good reason for it to slow down more than that when it's used the same way. If you have a reason go ahead and tell me. > Again, latency isn't about how many times something is called per second. That would matter for throughput. I addressed both. The extra latency for using an overly capable lock should be negligible. That's not the problem anyone is worried about.
        CyberDildonics 5mo ago
        Basic coding knowledge and an assumption of competency. This is just saying "I just know", but what specific function and basic timings are you going off of? If you don't know, why are you so sure of the numbers? The whole point of the complaint was wtallis claiming the inter-process-capable lock was being used for locks that don't need it! That's the foundation of this conversation! They were saying it's rare to need IPC lock for video games and I don't think that's true, then I gave a scenario where you would use one.
        Dylan16807 5mo ago
        If you're not actually using it between processes, the overhead could be as small as an extra conditional. For an upper bound I think a couple wasted syscalls makes sense. Why would it be significantly slower than that? But whatever, let's focus on the actual point: > They were saying it's rare to need IPC lock for video games and I don't think that's true, then I gave a scenario where you would use one. And I was pointing out that a voice IPC lock is still "rare" when we use the most appropriate definition of "rare" for this context. In this context of worrying that using the wrong kind of lock will slow the game down, how often we're using the lock matters. If we go 50 million CPU cycles between uses, it's "rare".

Dylan16807 5mo ago

What specifically are you saying can make a difference? I'm saying that extra overhead from making your lock work across processes should be very tiny. That overhead shouldn't add much more than a microsecond in either latency or CPU usage, compared to an in-process lock.

CyberDildonics 5mo ago
You were saying "reasonable overhead" makes no difference because something "isn't called much". This is not only ambiguous but also not true because latency is important. What calls specifically are you talking about between windows and linux? This was started by someone talking about WaitForMultipleObjects.
- Dylan16807 5mo ago
  I wasn't excusing all overhead, I was excusing the difference in overhead caused by making the lock more flexible. Because that's what the discussion is about, a lock that can be shared between processes versus a lock that can't be. The penalty for being "too flexible". But assuming reasonable implementations, the difference between those two lock styles shouldn't be more than about a microsecond, should it? So that's fine for a lock that's only used 100 times a second. I'm not comparing windows and linux anywhere.
  - CyberDildonics 5mo ago
    I was excusing the difference in overhead caused by making the lock more flexible What are the two functions you're comparing and what is the actual difference in overhead that you're talking about? a lock that can be shared between processes versus a lock that can't be. This is a dramatic black and white difference, these would be used for two different things. In that case it's apple and oranges, one would be for interprocess communication and one wouldn't. the difference between those two lock styles shouldn't be more than about a microsecond, What are you basing this on? Do you have an examples or benchmarks of the actual calls and their timings? fine for a lock that's only used 100 times a second. Again, latency isn't about how many times something is called per second. That would matter for throughput.
    - Dylan16807 5mo ago
      > What are the two functions you're comparing Go ask this comment, because I'm continuing their comparison: https://news.ycombinator.com/item?id=48125795 https://news.ycombinator.com/item?id=48125795 > In that case it's apple and oranges, one would be for interprocess communication and one wouldn't. The whole point of the complaint was wtallis claiming the inter-process-capable lock was being used for locks that don't need it! That's the foundation of this conversation! > What are you basing this on? Basic coding knowledge and an assumption of competency. There's no good reason for it to slow down more than that when it's used the same way. If you have a reason go ahead and tell me. > Again, latency isn't about how many times something is called per second. That would matter for throughput. I addressed both. The extra latency for using an overly capable lock should be negligible. That's not the problem anyone is worried about.
      - CyberDildonics 5mo ago
        Basic coding knowledge and an assumption of competency. This is just saying "I just know", but what specific function and basic timings are you going off of? If you don't know, why are you so sure of the numbers? The whole point of the complaint was wtallis claiming the inter-process-capable lock was being used for locks that don't need it! That's the foundation of this conversation! They were saying it's rare to need IPC lock for video games and I don't think that's true, then I gave a scenario where you would use one.
        Dylan16807 5mo ago
        If you're not actually using it between processes, the overhead could be as small as an extra conditional. For an upper bound I think a couple wasted syscalls makes sense. Why would it be significantly slower than that? But whatever, let's focus on the actual point: > They were saying it's rare to need IPC lock for video games and I don't think that's true, then I gave a scenario where you would use one. And I was pointing out that a voice IPC lock is still "rare" when we use the most appropriate definition of "rare" for this context. In this context of worrying that using the wrong kind of lock will slow the game down, how often we're using the lock matters. If we go 50 million CPU cycles between uses, it's "rare".