But that goes back to "how often". Not how many games use it, but how many times per second they use it. You might touch your voice process lock once per frame? That's negligible in terms of CPU time. Any half-reasonable overhead makes no difference in that lock, but might have a big impact in a more common lock.
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.
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.
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.
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.
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.