Comments on Rational Java: Let's pause for a Microsecond

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2017-11-22T07:59:39.272+00:00

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Yes you are correct there will be a difference acr...

2015-11-03T14:22:46.397+00:00

Yes you are correct there will be a difference across OS and hardware. My timings were on a MBP when connected to the mains (strange things happen when on battery). The point of my article however I do think holds true.

I always thought Thread.Sleep accurracy was highly...

2015-11-03T14:15:49.966+00:00

I always thought Thread.Sleep accurracy was highly dependent on the OS and versions of Windows in particular historically (/for instance) could show some wild variation (unless you played with some settings around hr timers). Which OS did you test ? Linux ?

Thanks, nice post

2015-11-02T05:17:21.235+00:00

Thanks, nice post

Thread.yield() takes ~0.3us - the equivalent of 7 ...

2015-10-30T12:32:55.578+00:00

Thread.yield() takes ~0.3us - the equivalent of 7 calls to System.nanoTime().
Of course I'm averaging the times for calls in tight loop. A single call to Thread.yield() on unwarmed code took ~15us.

Ok so it is to implement a rate control then. Make...

2015-10-30T10:53:24.701+00:00

Ok so it is to implement a rate control then. Make sense now.
By the way, how Thread.yield behaves in this regard ? (on linux at least)

In this case I want to pause a publishing thread e...

2015-10-30T09:30:16.266+00:00

In this case I want to pause a publishing thread exactly 1us between sending events.

Well, my point is: Generally if you want to wait ...

2015-10-30T07:37:51.896+00:00

Well, my point is:
Generally if you want to wait it is to relax the system and let other thread progress. In this regard, LockSupport.parkNanos(1) relax pretty well the system. Using a busy wait will not let other thread progress on the core you are running. You can afford that, but, then, I do not see the point to busy waiting for a time period. Usually you want to spin checking a volatile flag indicating data are ready. So between busy waiting for 10us or a basic spinning it makes no difference on the core execution.

Cheers

Thank you for this very interesting post.

2015-10-29T21:02:37.552+00:00

Thank you for this very interesting post.

Always nice to hear from you! Thanks for typo - fi...

2015-10-29T10:32:06.059+00:00

Always nice to hear from you!
Thanks for typo - fixed.
I have no problem with a basic spin loop to achieve the busy wait for my application. Happy to dedicate a CPU to that.
Added comparisons for LockSupport.parkNanos(x). As you can see it's not really useful if you actually want to wait 1us.
Cheers

It is System.nanoTime, not Sustem.nanoSecond. Wha...

2015-10-29T07:23:00.342+00:00

It is System.nanoTime, not Sustem.nanoSecond.

What's the point to wait 1us or more by executing code ?
Let's burn the core by spinning this is the same thing. I do not think you relax more the system by calling System.nanoTime compared to a basic spin loop.
LockSupport.parkNanos(1) seems more efficient to achieve the goal.

Cheers