RFR: 8305092: Improve Thread.sleep(millis, nanos) for sub-millisecond granularity [v7]

[Aleksey Shipilev]

On Thu, 20 Apr 2023 02:14:53 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Adjust test times
>
> src/hotspot/os/windows/os_windows.cpp line 5263:
> 
>> 5261:   if (nanos_left > 0) {
>> 5262:     millis++;
>> 5263:   }
> 
> You could simplify this to:
> 
> if (nanos > millis * NANOSECS_PER_MILLISEC) {
>   millis++;
> }

True, simplified.

> src/hotspot/os/windows/park_windows.hpp line 53:
> 
>> 51:     void park () ;
>> 52:     void unpark () ;
>> 53:     int  park(jlong millis);
> 
> While you are here could you get rid of the spaces on park/unpark before the parentheses - thanks.

Right, did so.

> src/hotspot/share/runtime/javaThread.cpp line 1983:
> 
>> 1981: }
>> 1982: 
>> 1983: bool JavaThread::sleep(jlong millis) {
> 
> Perhaps a comment:
> 
> // Internal convenience function for millisecond resolution sleeps.

Added!

> src/java.base/share/classes/java/lang/Thread.java line 1:
> 
>> 1: /*
> 
> Why doesn't `Thread.sleep(long millis)` simply call `Thread.sleep(millis, 0)` instead of duplicating most of the code?

That would change the stack depth, for which some tests are sensitive. https://github.com/openjdk/jdk/pull/13225#issuecomment-1514461529. I think merging `sleep` implementations is something to do in a targeted cleanup, which would handle those test updates too.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13225#discussion_r1172237713
PR Review Comment: https://git.openjdk.org/jdk/pull/13225#discussion_r1172238273
PR Review Comment: https://git.openjdk.org/jdk/pull/13225#discussion_r1172237000
PR Review Comment: https://git.openjdk.org/jdk/pull/13225#discussion_r1172236374